We have had a few members who’ve had issues with that, it could well be that the spinal accessory nerve has been irritated during surgery.
Shoulder pain and weakness after surgery - General - Living with Eagle
We had a couple of members last year I think who had quite severe post op arm symptoms but I can’t find their discussions atm- they posted quite a bit of info about slings, PT etc that they had found.
I hope that this improves soon for you 
1 Like