It's not the shoulder, but I don't quite know how to describe it.
When I row, the right shoulder blade feels like it is sliding out of place.
It feels like it is being pulled forward when it should stay put.

I've never even heard of this one, and it has me scratching my head.

Edit, I just tried it with a heavier band. There is a pop; which I think
means the ball is sliding around in the joint.

So now I am guessing there is some swelling in the shoulder joint,
and that is causing the ball to come partly out of the socket.