It's probably about the size of a quarter, maybe a half dollar. The lump
seems to be confined to just one rib
. Oh, and it's not really painful to the touch, but it's hard to tell, because I've been poking at it so much.
Does anybody know what it could be? Do ribs sometimes just grow like that? I'm a 17 year old male, by the way, and something of a hypochondriac.