Cardiology question

[blacksmoke]

I have had a feeling of pressure in my arm, right under the deltoid, while resting durring strenuous exercise. It has happened a about 3 times in the past year durring cross fit. I don't want to confuse this with defered pain from heart problems and was wondering if anyone else ever experiences this type of feeling while doing strenuous exercise of that type. It's not a pain I would usualy even mention except for the fact that I just learned about defered pain today in physiology class. I read that CAD is one of the main causes of otherwise heatly,fit people having a heart attack after exercising.
I have had an ECG about two years ago in response to a doctor making a mistake durring a physical and thiniking that I had a heart murmur. The cardiologist who performed the test said I had "a textbook heart" and ruled any heart defects as far as she could tell. I remember her saying my valves were working perfectly but do not remember if the coronary arteries were part of the examination. Is anyone familiar with these ECGs and would that have showed narrowing or blockage in a coronary artery? I would like to add that I have never had any other symptoms related to heat problems and as far as I know am in great health.