Scapula Sideways Stretch
Gently raise one arm [say the right] directly above your head then slowly bend it at the elbow and place your finger tips between your shoulders at the base of your neck and as far down the spine as you can. Try keeping the upper arm as vertical as possible. Now carefully reach across behind your head with the left arm and take hold of the right elbow. Once you have a grip, try gently drawing your right elbow across toward the midline [in other words across and toward your left shoulder]. As you do this, you will feel your right shoulder blade [scapula] rotate outward and the area surrounding your right armpit stretch. Hold gently for 30 seconds if you are able. If this causes you to get to 7 or higher out of 10 on the pain scale, reduce the intensity and/or the duration and build up to 30 seconds as you are able.
Now repeat on the other arm.