What could a tender lump on right side of rib cage mean?

Answer:

The first thing I'd expect it to be is an insect sting or bite. It's also possibly a tumor or cyst, but then I need to mention (as everyone worries) that malignant tumors generally don't hurt -- so it's not likely that. Another possibility is an abcess or even a simple bruise or strain.

If you're worried, by all means get it checked out, but it's likely not a problem.

First answer by Cjonb. Last edit by Cjonb. Contributor trust: 1198 [recommend contributor recommended]. Question popularity: 1 [recommend question].