You should also know that women often have heart attacks with absolutely NO pain. Men don't always have pain either. I honestly can't tell from your post if you're a woman or a man!
Did you get copies of everything that they did? If not, call and get them (they should be free). Sometimes ER docs do not tell you everything.
You may have to do doctoring with more than one specialty. I hope you have a primary doctor who can coordinate it all for you.
One of my pet peeves with doctors is when they don't find anything right away and declare that you're fine. No way is someone fine with the symptoms you're having. All it means is that the right testing wasn't done yet. Or the right thinking.
Just go in if you get worse.
Annie