Here's a great stretch that you can do any time to release tension in your back, chest and shoulders. It is excellent to do after prolonged periods of sitting at a desk, in a car or in an airplane.
Kneel on a padded, flat surface or on a yoga mat with your knees hip-width apart and directly below your hips. Place the palm of your left hand directly below your left shoulder and place your right hand slightly in front of your right shoulder. Be sure you don't sit backward toward your heels: Your hips should remain above your knees for the entire stretch.