context: If you've been sidelined by a sore back, you're not alone. Four out of five people experience back pain at some point, making it the second most common reason for visiting the doctor. Back pain takes various forms, from a persistent dull ache to sudden sharp pain, and has many causes. Sometimes it results from a sprain, fracture, or other accidental injury. It can stem from a disease or medical condition, such as arthritis, fibromyalgia, or spinal stenosis (a narrowing of the spinal canal through which the spinal cord runs). Many people develop back pain in part because they're overweight or sedentary. The good news is that most lower back pain usually gets better within a few days or weeks, and surgery is rarely necessary. What's more, simple self-help strategies such as these can be surprisingly effective at preventing back pain and keeping it from returning: 1. Get more exercise. If your back is hurting, you may think the best way to get relief is to limit exercise and to rest. A day or two of rest may help, but more than that may not help the pain. Experts now know that regular physical activity can help ease inflammation and muscle tension. 2. Watch your weight. Extra pounds, especially in your midsection, can make back pain worse by shifting your center of gravity and putting strain on your lower back. Staying within 10 pounds of your ideal weight may help control back pain. 3. If you smoke, stop. Smoking restricts the flow of nutrient-containing blood to spinal discs, so smokers are especially vulnerable to back pain. 4. Sleeping position. If you're prone to back pain, talk with your doctor about the best sleeping position. Sleeping on your side with your knees pulled up slightly toward your chest is sometimes suggested. Prefer to sleep on your back? Put one pillow under your knees and another under your lower back. Sleeping on your stomach can be especially hard on your back. If you can't sleep any other way, place a pillow under your hips. 5. Pay attention to your posture. The best chair for preventing back pain is one with a straight back or low-back support. Keep your knees a bit higher than your hips while seated. Prop your feet on a stool if you need to. If you must stand for a prolonged period, keep your head up and your stomach pulled in. If possible, rest one foot on a stool -- and switch feet every five to 15 minutes. 6. Be careful how you lift. Don't bend over from the waist to lift heavy objects. Bend your knees and squat, pulling in your stomach muscles and holding the object close to your body as you stand up. Don't twist your body while lifting. If you can, push rather than pull heavy objects. Pushing is easier on the back. 7. Avoid high heels. They can shift your center of gravity and strain your lower back. Stick to a one-inch heel. If you have to go higher, bring along a pair of low-heeled shoes and slip into them if you become uncomfortable. 8. Stash the skinny jeans. Clothing so tight that it interferes with bending, sitting, or walking can aggravate back pain. 9. Lighten your wallet. Sitting on an overstuffed wallet may cause discomfort and back pain. If you're going to be sitting for a prolonged period -- while driving, for example, take your wallet out of your back pocket. 10. Pick the right handbag or briefcase. Buy a bag or briefcase with a wide, adjustable strap that's long enough to reach over your head. A messenger bag (like the ones bike messengers wear) is made to wear this way. Having the strap on the opposite shoulder of the bag distributes the weight more evenly and helps keep your shoulders even and your back pain-free. When carrying a heavy bag or case without straps, switch hands frequently to avoid putting all the stress on one side of the body. To lighten the load, periodically purge bags, cases, backpacks, and other carriers of things you don't need. 11. Forget about back braces. Various back supports are available, from elastic bands to special corsets. They can be helpful after certain kinds of surgery, but there is not much evidence that they help treat chronic back pain.