This video demonstrates how to increase the upper back flexibility by using a towel. This exercise is suited for someone with a very stiff upper back.
Caution: If you experience discomfort during this exercise, you can decrease the duration and decrease the height of the towel. If you have a very stiff upper back and your head does not touch the floor, you may place a thin pillow underneath your head for support until your upper back becomes more flexible. If the discomfort persists, stop the exercise and consult with your health practitioner.