So, I've been doing the prescribed exercises faithfully - 30 times walking the fingers of my right hand up and down a wall - fifteen times facing the wall, fifteen at right angles to it, all the while keeping my right scapular in and down, morning and evening. It was amazingly painful both during and after, but I know that it's supposed to hurt and while I don't like pain, I'm not going to run from it. Especially if it will mean less pain down the road.
And. It's been four days, and there is less pain. The exercise still hurts, but not as much, and this morning I was able to move my right arm more easily than I have been. Of course, I've been avoiding putting my right hand above my shoulder (just try washing your hair that way!) and I switched from a shoulder bag to a backpack, so that had to help, too, and I'm using my left arm more for the same reason.
Whatever it takes - it's working. I'm glad.