For some years now I have had an ache around my lower left rib cage. It's not getting worse but its not getting better. It ranges from a niggle then sometimes will worsen to a mild pain. I do sometimes smoke (maybe 3 on the odd occation if I'm out) which makes it feel worse. The left side of my rib cage ( the side the pains on) does protrude more than my right. I did have a ECG due to sudden chect psins but that was fine. I'm 35 and other wise in good health. I do run and this has no effect on the ache. I don't suffer with any coughing but it can feel worse if I lie down and take deep breaths. Any indication in this I should be worried?