Position: On back with a big pillow
Affects neck, throat, chest
Although sleeping on your back may seem innocuous, if you've got a thick pillow under your head, your neck pays a steep price. "A thick pillow pushes your head forward, exactly opposite the natural curve of the spine in the neck," says Kirsch. Neck pain and headaches can result. This position also impedes the flow of air through your throat and closes off the top of the chest, which decreases breathing capacity.

Pillow talk
Back sleepers who still want a pillow should choose the thinnest one they can stand. A soft down pillow compresses the most. If you often wake up during the night with a neck ache or headache, Kirsch recommends keeping a small neck-roll pillow (such as the Silk Neck Pillow, available at huggermugger.com) on hand: Remove your pillow and place the roll under the back of your neck for several minutes to reset the spinal curve and ward off further pain, then go back to sleep using your usual pillow. Or create your own neck roll by tightly rolling a thin bath towel.

Fix: neck release
What it does: Balances and stretches the neck muscles, freeing the vertebrae in your neck to find their natural alignment.

How to do it: Sit tall on the edge of a chair. Drop your right ear toward your right shoulder until you feel a strong yet bearable stretch. Hold for five breaths. Return to center, then drop your left ear toward your left shoulder and hold for five breaths. Return to center. Turn your head as far as you comfortably can to the right; stay for five breaths. Come to center. Repeat to the left.

Fix: reclined heart opener
What it does: Opens the chest and encourages the head and neck to move backward. Stretches the anterior longitudinal ligament, which can shorten when you spend too much time with your head in a forward position.

How to do it: Lie flat on a mat on the floor with a rolled up blanket or towel placed horizontally under your shoulder blades. Rest your arms out to the sides in a T, palms facing up. Relax and breathe deeply for at least two minutes, gradually working up to as long as 15 minutes.