Broken ribs long since healed? Could I really have broken at least 3 ribs when I was 10 and not know it?

On the left side of my chest I have a rather large, baseball sized, tissue lump that doctors have seen did an ultrasound and determined was not a tumor and quickly lost interest. The lump is on my ribs, on said left side my rib cage stops about an inch sooner than on the right side an if I put pressure on what I call "the bump" I become nauseous very quickly, I can not lay on it comfortably. I discovered size bump when I was 16 (now 21) and I have no idea where it came from, I was a ruff n tumble Tom boy and took plenty of falls and hits I probably shouldnt have. I can recall chest pains in the effected area since I was about 10 or 12. Does this sound like healed ribs? What the heck is it? Have anyone heard about something like this? I can now touch it without pain but weight or pressure on it is not tolerated long. Does this sound familiar to anyone? Please help the docs don't seam to care about it but it effects me greatly.