Left rib cage swollen and painful, clean xray, ultrasound, and ct. what to do now?

Musculoskeletal : Rib cage pain can be due to problems in any of the building blocks of that structure. Negative imaging of the bony elements is reassuring however a good clinical exam performed correctly should help to further narrow down a possible cause. If this is a nerve or muscle issue further imaging may not be helpful although your doc may consider an MRI or bone scan. A trial of therapy may be indicated.