It began as a twinge. Then the pain started to radiate down my back when I biked. Bothersome became dangerous when it hurt to turn my head; do not try cycling with impaired neck mobility. I wondered: “Why does my back hurt?” Yet, I saw no reason to modify my fitness routine. I pedaled. I kickboxed. I lifted weights. And after about three weeks, I paid the price. One sleepless night, pain that felt like a knife in my back pinned me to the couch.

Whether you’re a week­end warrior, an elite athlete, or somewhere in between, there’s a strong chance that eventually you’ll deal with back pain, too. In fact, Georgetown University experts estimate a whopping four in five people suffer from back pain. Here’s why: Everyday activities that you do without thinking—sitting at the computer, slipping on a pair of shoes, crawling into bed at night—can make or break your spine health.

Most aches are caused by strains (injured muscles or tendons) or sprains (damage to the tough fibrous tissue, or ligaments, located where your vertebrae connect to joints). These injuries are typically brought on by over­use, a new activity, excessive lifting, or an accident. Other times, a compressed (aka pinched) nerve, such as in a herniated disk, is to blame for the ache.

Why Does My Back Hurt and What Can I Do to Fix It?

Given the prevalence of back pain, you would think there would be a go-to treatment for it down pat. Not even close.

“The challenge is that you can’t see injuries to tendons, ligaments, and muscles the way you can bone fractures and herniated disks,” says Jeffrey Katz, M.D., a professor of medicine and orthopedic surgery at Brigham and Women’s Hospital in Boston and the author of Heal Your Aching Back. Despite diagnostic advances, doctors can’t pinpoint an exact cause for as many as 85 percent of people who ask, “why does my back hurt?” That makes these cases quite tricky to treat, as you might guess. Spinal manipulation, for example, is controversial—some docs say it does more harm than good—but it’s the only remedy that got me off the couch and back on my bike.

“Chiropractic care is not without concerns; then again, neither is traditional medicine, particularly when you’re dealing with a problem like back pain, which has no easy, one-size-fits-all fix,” says Mark Moyad, M.D., the director of preventive and alternative medicine at the University of Michigan Medical Center.

Even exercise, which a majority of experts agree is one of the best ways to maintain a healthy back and chase away aches and pains, can be problematic. “When you’re sedentary, the muscles supporting the spine get weaker, and you’re more prone to injury,” says Dr. Katz. But “exercising with improper form—rounding the back when doing deadlifts or arching it during ab work—can place unwanted stress on the spine,” explains Robyn Stuhr, an exercise physiologist and vice president of Exercise is Medicine (EIM) at the American College of Sports Medicine (ACSM).

If you fall into the 80 percent of the population that regularly suffers from back pain, take heart: One-third of aches due to a strain or a sprain improve in a week without medical intervention (the remainder may take up to eight weeks). But unless you do some spine tuning—strengthening your back through exercises and fostering healthier habits with the advice here—your odds of a recurrence within six months are about one in three, according to Dr. Moyad. Keep your back in tip-top shape—and put an end to wondering why does my back hurt?—by avoiding these seven things that may cause back pain.

7 Common Causes of Back Pain

You spend too much time in front of a screen.

Nine hours—that’s how long the average person spends hunched over or slouched in front of a screen each day. Beyond working over a computer, increased time on phones and tablets is creating more aches and pains in your shoulders, necks, and backs, according to a Temple University study. “It’s important to take breaks, do neck exercises, and occasionally hold your phone or tablet out in front of you,” says Deborah Venesy, M.D., a doctor of physical medicine and rehabilitation at the Cleveland Clinic Center for Spine Health. For a simple neck reliever, hold your head for 10 seconds in each of the following positions: forward, back, left, and right. Repeat this five times a day.

Sitting all day is hazardous, too. “It puts more pressure on disks and vertebrae than standing or walking,” says Dr. Katz. Alleviate the tension with an office makeover. Start with a lumbar-support cushion. Then adjust your seat so your computer monitor is at eye level, your arms and knees are bent at a 90-degree angle, and your feet rest on the floor. Finally, go to workrave.org to download a free program that flashes screen reminders to take computer breaks as often as you schedule them.

You ignore your core.

When you hear the word core, you might picture six-pack abs. But your core is composed of much more: Back, side, pelvic, and buttock muscles all work together, along with your abs, to allow you to bend, twist, rotate, and stand upright.

“Your core is like a crane that supports all of your movements,” says Dr. Moyad. Unlike crunches, which focus solely on abdominal muscles, core exercises—lunges, squats, planks, and others—strengthen several spine-supporting muscle groups at once.

You sleep on your stomach.

If you wake up and wonder, “why does my back hurt?” odds are your sleeping position is to blame. The bedtime belly flop places pressure on joints and muscles, but sleeping on your side or back keeps your spine elongated and neutral. If you must snooze on your tummy, slide a thin pillow under your hips to alleviate pressure on disks, ligaments, and muscles.

Regardless of your slumber sweet spot, go with a medium mattress (check the manufacturer’s scale of firmness and opt for one in the middle range) and a pillow that keeps your head in line with your spine. Research in The Lancet found that people with chronic low-back pain who snoozed on medium mattresses had fewer aches after three months than those who slept on firm beds. So take a tip from Goldilocks: Your bed should be not too hard (this wreaks havoc on hips and shoulders) and not too soft (this puts your back and joints out of whack).

You smoke. 

Cigarettes don’t just wreak havoc on your heart and lungs. “Smokers have a higher incidence of recurring back problems,” says Dr. Katz. The cause and effects of this are many. Nicotine restricts blood flow to vertebrae and disks, so they may age and break down more quickly. It may also interfere with the body’s ability to absorb and use calcium, leading to osteoporosis-related bone and back problems. You know what you have to do: Quit. Go to smokefree.gov to customize your own smoking cessation plan.

You’re struggling with mental illness.

It’s no secret that struggling with pain can take a toll on your mental health, and studies have shown that people with back pain are more likely to be depressed. But now doctors are discovering that the reverse may be true as well: In research from the University of Alberta in Canada, people with major depression were four times as likely to develop disabling low-back and neck pain.

Some scientists believe that poor coping skills related to depression, such as withdrawing or avoiding problems, may trigger the release of the stress hormone cortisol, causing back and shoulder muscles to tense up and spasm. “The result can be a devastating cycle of chronic pain and depression,” says Dr. Moyad. Antidepressants as well as natural mood- and mental health-enhancers like exercise, meditation, yoga, and deep breathing can help ease stress and make you feel better.

Your shoes aren’t supportive.

Sure, sky-high stilettos are a no-no, but it turns out that flats can cause back pain too. “Sandals and flip-flops often provide little, if any, arch support. Continuous wear can lead to back, knee, and foot problems down the line,” says Megan Tabor, a chiropractor at the Osher Clinical Center at Brigham and Women’s Hospital. But don’t worry: You needn’t settle for all function and no flair. Alternate styles throughout the week—from high to low, sneakers to sandals—and avoid wearing a particular pair every day. “Shoes should fit properly and offer good arch and heel support,” says Tabor.

If you walk to work or the bus stop, wear shock-absorbing sneakers, then slip on cuter kicks once you get to the office.  Your purse could also be to blame, especially if it’s huge and you’re lugging it on one shoulder. Try a tote with a wide, padded strap; carry it messenger style; and lighten the load. Pro tip: Your bag should weigh less than 10 percent of your body weight, according to the American Chiropractic Association,

You stop—instead of swap—your activities. 

Lying down minimizes stress on the lumbar spine; however, staying sedentary for more than a day or two can actually prolong and worsen pain. In a new study from Sweden, back pain sufferers who remained active recovered more quickly and felt less depressed than those who took it easy.

“Low-impact activities like walking and swimming boost blood flow to back muscles while relieving pain and stiffness,” says Dr. Venesy. Yoga, with its emphasis on stretching and strengthening, may be one of the most effective spine soothers. After three months of weekly sessions, 60 percent of back-pain sufferers who participated in an Archives of Internal Medicine study reported less discomfort, and 40 percent were able to cut back on pain meds.

Fast Fixes for Acute and Chronic Back Pain

When pain strikes, follow these rules for fast relief.

• Get out of bed. If you must lie down, do so for a few hours and for no more than a couple of days. Light activity is best. (Consider this active recovery day as a good schedule to try.)
• Pop an OTC pill. Nonsteroidal anti-inflammatory drugs, like ibuprofen and naproxen, reduce inflammation better than acetaminophen. Don’t wait for pain to flare up and be left wondering ; take as directed on the label.
• Alternate hot and cold. Apply a cold compress right after an injury to numb pain sensors and reduce swelling. Switch to heat after 48 hours to stimulate blood flow to the area and soothe aches.
• Stay balanced. Bend at the knees to pick up (lightweight!) items; carry them close to your body to minimize pressure on your back. Don’t sit down or stand up too quickly.

How to Treat Chronic vs. Acute Back Pain

Acute back pain comes on suddenly but improves over time; chronic pain worsens and can last months. If you don’t feel better after three to four days, see your primary care physician. She may refer you to a neurologist or a neuro­surgeon if the pain is nerve-related; an orthopedist, osteopath, or chiropractor for musculoskeletal problems; a rheumatologist for joint problems; or a physical therapist or physiatrist for rehabilitation exercises. Back specialists typically recommend one or more of the following strategies:

Chiropractic Care

• Treatment: Chiropractic care restores mobility by manipulating joints and the spine; it often incorporates massage. (ICYMI, here’s the difference between flexibility and mobility.)
• Best for: Acute back pain; not for those with nerve impairment or herniated disks
• Find a pro: The American Chiropractic Association and your state’s Board of Chiropractic Examiners (visit their website and search for your state).

Massage

• Treatment: Therapeutic, Swedish, or sports massage uses pressure to stretch and stimulate blood circulation to muscles, ligaments, and tendons.
• Best for: Chronic low-back pain
• Find a pro: National Certification Board for Therapeutic Massage and Bodywork.

Acupuncture

• Treatment: Acupuncture may block pain signals and/or release endorphins.
• Best for: Chronic low-back pain
• Find a pro: National Certification Commission for Acupuncture and Oriental Medicine.

Cognitive Behavioral Therapy

• Treatment: Cognitive behavioral therapy teaches mind-body techniques to help manage chronic pain.
• Best for: Chronic back pain
• Find a pro: Association for Behavioral and Cognitive Therapies.

Muscle Relaxants

• Treatment: Muscle relaxants provide short-term pain relief from severe muscle spasms.
• Best for: Acute low-back pain
• Find a pro: Your primary care physician or a specialist can prescribe these drugs.

Exercise

• Treatment: Exercise, such as yoga, stretching, or strength training, improves mobility.
• Best for: Acute and chronic low-back pain
• Find a pro: American Academy of Physical Medicine and Rehabilitation, American Physical Therapy Association, or Association of Academic Physiatrists