I had an overweight 22 year old kid come into my office the other day scared to death he had cancer because his girlfriend found a small lump in his belly. I knew as soon as I felt it that it wasn't cancer but rather a fatty buildup. This is just one of the scary but non-life threatening things that can happen when you are overweight. I told him that if he lost some weight it would go away and not be a problem again.
NOTE: If you feel a bump get it checked out. It's not worth the risk to not do so.