question: My mom has a lump on her rib cage right next to her right breast under her arm. The lump about 1 to 2 inch away from it. it is about the size of two thumb nails put together. She says she can feel it when she lets her arm down and that it only feels on the right side and nothing on the left. She first felt it around 2 to 3 months ago. Any idea what it could be? She is scared that it might have to do something with breast cancer. Thank you.