in my case, w the collarbone, PT said to do lat pull down to strengthen trapezius to pull shoulder back and take some of the load off of the joint.
Don't know if that applies to you, but I feel your pain, or something like it anyway.
It does not seem that any exercise helps my shoulder and tends to hurt it more. Cant wait to try skiing, that will be a big decision if I can stand the pain or it wont bother too bad. Have not really been on the Nordic track much either, I need to pull that into the house from the garage.