Been having very uncomfortable issues under ribcage on left side, like something that should not be there?

Get an ultrasound: Under the left side of your ribcage is your spleen and the vessels that run through it. A noninvasive procedure, ultrasound, can start the process in figuring out why you are experiencing discomfort. I would also suggest having your doctor give you a thorough exam, including a chest exam and perhaps an xray. Be sure to discuss any other symptoms with regard to breathing and movement.

Need cxr: I advise a chest x ray just to be safe and especially if you smoke. If notihing shows, you may need a ct scan but most often, something will show on cxr. If nothing shows on cxr, perhaps pain is more musculoskeletal which may come from overuse of those muscles such as in lifting, reaching even extensive coughing over a period of time.