Chest pain, over 2 years now. Had multiple chest x-rays, blood tests, etc. Nothing to do with my organs. Yet..?

Could it be arthritis? It doesn't always hurt but when I go into certain posistions it becomes apparent (especially when slouching.) My mother suffered from carple-tunnel syndrome and also had problems with arthritis. I thought it was my lungs or my heart, or GERD, for a long time but the docotrs are sure that its not. Could it be this? Or some other bone problem?