Numbness and/or an unusual sensation after surgery is not unusual, and yes, it may well be caused by damaged nerves, but I have not experienced any pain from that cause. My armpit was very numb and has gradually returned to something like normal. As more surgery is scheduled soon, you may have to wait until that is completed and see what the situation is but I would certainly be asking for more information about cause and alleviation of symptoms. Nerve damage can improve over time.