My father have Gas issue. Though nothing gets detected in his tests. He have had Endoscopy n Angiography to make sure. He earlier used to have chest pains as well which now has decreased to a level. But sometimes it pains a little. Sometimes his back tightens up. This is the major issue that he is experiencing, which is the back is tightening up. I think if it is an acid issue. Please confirm what it could be