The unmeetable deadline, the never-satisfied boss, the you-don’t-deserve-him mother-in-law: We all know how pressure and aggravation make us feel. Not just in terms of emotional stress (that’s a given), but how they tangibly, really feel — the racing heartbeat, the churning gut, the dry mouth. Mental stress has always had its physical component. In fact, that’s what the stress response is: the visceral priming of the body to either fight or run away from a perceived danger. Less well recognized is that even chronic, unpleasant stress, the kind that’s so constant you consider it normal, can cause aches and pains that you might not attribute to emotions.

“Many people who have stress-related pain aren’t even aware of what they’re fearful or angry about,” says Ian Wickramasekera, Ph.D., clinical professor of psychiatry at Stanford University Medical School. By some estimates, half of the patients doctors see for various common body aches are actually expressing psychological distress through physical pain. Stress experts across the country saw evidence of this after the terrorist attacks last September. “In 30 years of specializing in stress-related diseases, I’ve never seen more flare-ups of physical pain, even in people who’d been free of symptoms for years,” Wickramasekera says. (Intrigued Stanford scientists immediately launched a study of the phenomenon.)

The source of stress-related pain lies in the brain, which, when you feel under the gun, triggers the release of cortisol, adrenaline and other hormones that prepare the body for action by, for example, increasing heart rate, blood pressure and respiration. Less noticeably, these hormones also make muscles tense up, which can cause aches and irritate nerves. Here’s a guide to the areas stress hits most often, and simple steps you can take to relieve the pain:

Low-back pain

Back pain can be caused by many different factors, such as poor posture or pressure on the spine from long hours of sitting. But a classic Swedish study of low-back pain in the workplace more than a decade ago showed that women who reported signs of stress such as dissatisfaction, worry and fatigue were more likely to experience low-back pain than those who had physical stressors like doing a lot of lifting. More recently, researchers at Ohio State University found that when volunteers felt stressed (from a snippy lab supervisor criticizing them as they tried lifting an object at a certain rate of speed), they used their back muscles in ways that made them more susceptible to injury. “I expect you’d see this even more in the real world, where stress is experienced over long periods and you care more about your task,” says study coauthor Catherine Heaney, Ph.D., associate professor of public health. To ease the twinge of low-back pain:

* Stand with your heels and shoulders touching a wall. Tilt your pelvis so that the small of your back presses against the wall, relieving back muscles. Hold for 15-30 seconds. Do this exercise regularly to reduce your risk of getting back pain or to relieve existing pain.

* Strengthen your abdominal muscles, which support the spine, by doing crunches three times per week Lie flat on your back on an exercise mat with hands cupped behind your ears. Feet should be together and flat on the floor, with knees bent at about a 45-degree angle. Curl your upper torso up, bringing ribs in toward hips until your shoulder blades clear the floor. Do one set of 15-25 crunches; gradually build to three sets. Also, increase endurance of the muscles along the spine, the spinal erectors, by doing alternate leg and arm raises from an all-fours position, holding each position for eight counts. Initially, do one set of 10 repetitions, building up to three sets.

Neck and shoulder pain

The neck is particularly prone to stress-related pain in part because it’s already bearing the burden of your 10-pound head. Pain may start with bad habits like squeezing the phone between your shoulder and your ear, but tension in neck muscles makes the problem worse, often causing pain to radiate. A recent study in Finland found that in addition to physical factors like working with a hand raised above shoulder level, mental stress is strongly linked to the likelihood of experiencing radiating neck pain. In most cases, getting rid of pain in the neck will benefit the shoulders as well. Here is what you can do:

* Give your neck muscles an all-around stretch one step at a time. First, while sitting erect in a chair, lower your chin to your chest, letting the weight of your head gently stretch tense muscles at the back of the neck. Hold the stretch for 15 seconds.

* Next, gently let your head drop toward one shoulder. Hold for 15 seconds and repeat on the other side.

* Use progressive muscle relaxation, in which you mentally focus on muscles and consciously allow them to relax. ‘First, you have to isolate the muscles by actually tensing them more,’ says Ronald Kanner, M.D., chairman of the department of neurology at Long Island Jewish Medical Center in New Hyde Park, N.Y. To do it, rest your elbows on your desk and press your face against your hands, then release, which will relax the muscles in your neck Mentally note the neck muscles you’re using and, over the course of about 15 seconds, slowly release their tension. Keep focusing on your neck muscles even after you lift your face from your hands, imagining the muscles deeply relaxing.