Hi Ridealot,
Hope things are getting better. Let me just tell you a true story. When I was a teen, a friend of mine dislocated his shoulder. They put a plaster stuff (I don't know the English word for it cascet?) on it to prevent the shoulder to move. The guy stayed up all night with an itch. After a few day, he decided he couldn't deal with it anymore and took the plaster stuff out (he broke it with some instrument - which apparently is not easy to do with only one valid arm). Anyway that guy's shoulder has been popping out ever since. He goes swimming: Ouach! the shoulder is dislocated again. HE supports some friends playing soccer, cheers loudly and raise his arms to the sky: ouach again. etc.
So the moral of the story is: whatever the doctor says... you should try.