I occasionally experience the same pain. I have had it for the past three months in a very cyclic pattern. I now have most of my gnawing pressure like pain on the left side under my ribcage. I had an ultrasound, upper GI series with small bowel follow through and blood tests for the mid stomach pain. All normal. Since I have been told by the dr. that my colon spasms and that is what causes my pain in my lower left pelvic region, I (and the dr.) are assuming for now that the upper mid and left discomfort/ache are due to my colon which passes through that area. I have lost 15 pounds becuase of the discomfort, but we can't seem to find anything else wrong. My dr. doesn't want to go in with a scope or colonoscopy since he says i am too young (25) and that my symptoms are not that severe (how would he know what it is like to live like this!!). I wish you luck in finding out what is wrong. If they don't go away I would see the dr.