Looking for other opinions here!
I was stretching in front of a mirror the other day and noticed a lump on my chest. 
Of the first ribs down from my collarbone, the rib on the left is flat and as I would expect it to be. The rib on the right either seems to stick out further or has a lump on it. The 'lump' is about an inch and a half long and maybe three quarters of an inch wide. I don't remember it being there before, but then I don't know if I would notice it being there before to be honest! (Being as I don't often prod myself in the chest or see my chest in mirrors that often! (usually just a small mirror to do my makeup in the mornings)).
I'm guessing it's probably just 'one of those things'. It doesn't hurt or anything. Can you have wonky uneven ribs?! 
My other ribs seem to be pretty symmetrical, it's the top one that the right one seems to stick out more than the left.