EKG and stress test clear, no GERD, but left arm and chest near heart mild discomfort. Worried if I will have a heart attack. 33 male no fam. History.

Data. At 33y/o with no ecg abnormality and a negative stress test, you probably are ok for the near term. There isn't enough information in your note to judge long term risk however. Mediterranean diet, not smoking, regular exercise and management of any risk factors you may have are prudent steps going into your future.