Pain

I was diagnosed with melanoa in October 2017.  I had surgery on my chest above mostly my right breast but a little above my left.  It was a very large scar and to remove it he went all the way down to the muscle on my chest.  Ever since then I have had pain in my underarms and on the sides of my breast.  It gets so bad that my arms feel like they are going to sleep.  I just had my ultrasound of my breasts done and they were normal.  He didn't think it should have spread because it was not a very deep spot.  I get worried about the feelings.  Has anyone ever had this happen?   What did you do?   I was doing yoga but at times it hurt more than helped.  

Any suggestions would be greatly appreciated :)

Melissa