I am not in pain, and it doesnt really hurt when i make it happen.. But for a long time now,(first starrted or noticed when i was 17 now 39).. my should clicks and grinds when i force it to move in cirular motion.. It is like its rubbing on my rib cage, because it makes one or more of my lower ribs collapse in a little? ? ? When i noticed this I went to my GP and I had my shoulder x rayed , it is normal according to the x-ray.. I complained and said well what is it, and I went back for further studies, by more specialist people and they didnt give a real answer saying it could be weak ligerments or miss shaped bone .. But the x ray was normal.. I wish I had a proper explanation, rather than possibilities..