If you have rib pain wihen inhaling or exhaling, it can have musculoskeletal origin, including the rib itself.
It's best to have it evaluated by a do, who is trained in nmm (neuromusculoskeletal medicine). So, they can assist in restoring function and reducing pain immediately. Since you are breathing while you eat, this may be aggravating it further. Also, posture has something to do with it too.