It is not likely to be a heat attack simply because you are 18 years old. But there are other causes, rarer and related to congenital abnormalities which can cause similar symptoms, for which I would say that you seek emergent medical attention. Go to an ER and seek their opinion, based on an EKG, and some lab work.
Chest pain is a serious biz, go and c a doc
now i feel a tightness in both of my arms with no current chest pain(that lasts longer then a few seconds)..should i be calling 911 or just wait?