muscle tear feeling?

On Nov. 7,2017 I had a modified radical mastectomy on my right side and a simple mastectomy on my left side. (Left side showed normal but I didn't want to face surgery again in the future so I had that removed as well, just in case). Anyway I am one month past surgery and doing well except that on my right side it feels sometimes like there is something loose under the skin below the incision almost like I would imagine a muscle tear to be, if that makes any sense. I am currently doing PT so that I can get range of motion back to be able to reach normally. I did have this sensation before PT so I'm wondering if this is normal. While driving or riding in a car if a bump is hit, it is very uncomfortable. Could it be just because of the extent of the surgery on that side. Any info would be appreciated. Thanks in advance.