Left intermittent pain under left rib cage. Sometimes comes when I take deep breath. What is it? Have had for about three weeks...Its a new kind of pain for me. Not sure what it could be.

You . You need to have a complete medical evaluation as it sounds as though your pain has been very persistent. Pain under the left rib cage could represent inflammation of the lining of the lung (pleurisy), infection, kidney issues, or even intestinal or pancreas issues. Please be seen immediately for an evaluation. If you had worsening pain, fever, cough, vomiting, shortness of breath, or light-headedness, then you would have to be seen as an emergency.