I have a firm lump in middle of rib cage above belly and below chest and its become itchy on outside what could this be?

Xyphoid bone: The location you describe is at the end of your sternum. Occasionally the xyphoid, (small bone/cartilage) at the end of sternum will dislocate and form a bump/lump. It is benign condition. A lateral chest x-ray should be able to show this condition. Okay to ask your doc at next visit.

Hard to say but...: Lipomas are commonly found lumps under the skin. But it's impossible to say without an exam. Your primary care doc should be able to make the call.