Exercise to stretch the back of your shoulder, your rotator cuffs.
On the back of your shoulder is a little muscles called Supraspinatus. Supraspinatus is very important for all mobility of your arms but is quick tricky to stretch. Some of the reasons why Supraspinatus, or the rotator cuff, might get injured are badminton, swimming, working in front of a computer,or as in my case; climbing.
This is a sitting version of the shoulder stretch but it works just as well when standing up.
This can be a difficult stretch so you need to take some time to feel into it.
Keep your left arm in front of you with forearm pointing straight up, palm facing you. Take your right arm and from underneath the left arm, grab the thumb of your left hand. To engage the stretch you gently pull your left arm out. Work against the pull by gently resisting with your left arm as if your were arm wrestling. You will feel tension on the back of your shoulder. Keep your right elbow positioned in front of your solar plexus to give support and help guide the movement. Hold the position for the desired amount of time and then switch to the other side.
A tip is to slightly extend the elbow of the side you are stretching. This will make the stretch even more effective.