It could be pneumonia, lots of people having walking pneumonia and dont realize it, slight fever etc. However, my husband had bouts of angina (chest pains) off and on for years. Sometimes bp normal, sometimes high. Last time we took him to hospital, same, Ekg, did treadmill stress tests excellent, blood work, etc. etc. Finally we told the doctor to do a heart cath, as we felt something was underlying cause of the chest pains, at first the doctor a cardiologist at that was reluctant, stating his immediate family history didnt indicate history, he didnt smoke or drink either, could of lost a few pounds but nothing major. He finally conceded to the test. My husband has a 50 percent blockage. No surgery, not that dire, but he did state it was good to catch now, so they could modify diet, use cholestrol meds to get rid of some of the plague built up in the ateries, that if we hadnt had the test, not immediately, but somewhere down the road, our worst fear would have been a reality. You know your body best, if it persist, you persist. Good Luck to you.
CrabbyRoad