Apanasana

Lower-back pain is the second-most common complaint, just behind headaches. A yoga pose, called apanasana, or knees-to-chest, gently stretches the lower back and hips. It can help relieve tension in the spine after a day of hunching over your computer or shoveling out from the latest snowstorm.
To perform the move, lie on your back and gently hug your knees to your chest. If this is uncomfortable, bring your legs slightly apart and hold the backs of your thighs instead. Be sure your lower back is flat against the floor. Breathe deeply and the hold the pose for seven to 10 breaths.