I have a muscle that is enlarged on my left shoulder, rsd is in left hand, and I think it is there because of the way I guard my hand whenever I'm having a flare. I have been on a major flare for the last month. I have also noticed my muslces on my left arm are an inch thinner than my right. I used to have a strong muscles from carving wood, but noticed they are gone now. I know rsd throws everything at us, and just wanted to see if anyone has seen this.