As for the EKG...that's not that big of a deal, really. I've had an EKG before and it's not bad at all. If you're having chest pains, then it sounds like it's important that you take the EKG, so you can find out if there's anything wrong. If the results turn out bad, just remember that no matter how much you feel like something like heart disease can ruin your life, you'll still be able to do many things you love. I've seen people go into major depression when they find out something is wrong with them, and then they pull out of it and become more active than ever. Just try to relax
As for the army...I don't really know what to say.
I wish you and your sister's fiancee the best of luck.
J3