I'm really worried about this swelling and pain I've been having in my lower rib cage for about a month now. It's pretty uncomfortable and sometimes I even feel a burning sensation. Occasionally, the pain seems to spread to my stomach. I've had some blood tests and an ultrasound, but they didn't show anything abnormal. Could you please help me understand what's going on?

It sounds like the pain in your lower rib cage could be related to muscle strain, costochondritis (inflammation of the rib cartilage), or digestive issues like acid reflux. Since your tests were normal, it might be worth monitoring your posture, stress levels, and diet, and if the pain persists, consulting a doctor for further evaluation.