An afternoon that could have been much better (or worse)

After a very alarming chest paint event that fortunately lacked the rest of the unwanted symptoms (like shortness of breath and extension of the pain to the back and/or the left arm) I rushed myself to Royal Victoria Hospital, just to be sure. After 2 hours of waiting and 3 hours of testing I was relieved to know that both my EKG and chest x-ray results turned out O.K.
So now I am kind of relieved that I do not have a heart condition, however, I am worried because I do not know what caused this thing (it happened 6 months ago also) and whether is going to happen again. Somehow, the words of the nurse that if I feel again any discomfort, I should have it checked and especially her view that this might be because of stress, are not very reassuring....
And then you tell me I am not getting old.....