I'm sure your doc already told you this but chest pain while playing tennis that goes away quickly sounds more like angina than a heart attack. IOW your episode was not a heart attack but rather a strong indicator that a future heart attack was likely and that further tests were warranted.

A real heart attack (MI) -- the kind that can kill you quickly -- is usually not exercise related and the pain continues for many tens of minutes without going away.

PSA: If you experience either type of symptom above, call 911. Don't wait around and don't drive yourself to the hospital. Take an aspirin if you have one handy and you're not allergic to it. Real aspirin, not ibuprofen or tylenol.

Since you mentioned take asprin, just curious , how does that help ?