Hi, I have a boney lump on my rib, right-hand side just below my collar bone, quite close to my sternum. It is like a thickening of the rib, is hard, not moveable and non-painful. Any ideas what this could be? I don't recall injuring the area at all. The lump is about 2cm long, along the line of the rib and quite shallow, I can just about see it in the mirror.