I did maybe 15 of those yesterday and man is my right shoulder sore this morning! Sore and feeling in better alignment. Wow.
Tell your PT to watch out because I am definitely coming to kidnap him.
I want to bring him home with me, or at least make him move next door to me For that first exercise, the "flossing", make certain that you are holding your shoulder down with that other hand so the nerve will glide properly.