About Two Years Ago I Started To "move My Rib

about two years ago I started to "move my rib under something". I did not notice anything was wrong until my friend noticed it and called it "shoulder thing" because when I did it I moved my right shoulder down. I tried to do it on my left side and couldn't. At first, I did it only once at a time, infrequently, and it was barely noticeable to others. I could easily resist it and did it like a habit, slowly it became more in a row, more frequently, more extreme, and harder to resist. Not like it's truly involuntary, but just something too habitus to resist forever, I might be able to resist a day if I set my mind to it. Just within 3 or so days, it has become painful, not severe, but like it's simply been over-worn, it hurts to laugh and appears it may be dangerous if unexamined.