Hey
Im a physio assistant and i can hook you up with some exercises if you would like.
Theres something called the supraspinatus.
It is part of the rotator cuff capsule that holds the shoulder blade in the socket and helps with rotation.
One of the key signs for supraspinatus is pain in the front and top part of the shoulder when placing your hand behind your back. There are different programs you can do to strengthen it. If youd like some ideas on some exercises let me know and ill see if ican put a program together for you. You are going to have to rest as well. Any socket or glide joint needs rest to repair or else your gonna have more and more and more reoccurances of shoulder pain. Your shoulder also is hurting for a reason. It hurts because the muscles and ligaments and tendons arent strong enough. YOU HAVE to build these up and strengthen them or your gonna be back into pain within two months again.
Let me know if you could use some help.