It could be some kind of heart burn or maybe it's gas. You can feel gas in all different parts of your body. But it's probably a good idea to see your Dr. to rule out anything serious.
How old are you? Heart attacks often mimic gas pain. There is really no way of knowing the difference unless you see a dr. I would go asap or call the ambulance if you are hurting that bad. Especially sweating, moving anywhere or with n/v, but I am not a dr-you should see one.
I agree - go to the ER. One of my best friends, who is in his early 30s, just had heart failure. You know how he got it? A virus!! A very healthy man, in great shape - but apparently there are these viruses floating around that can basically cause you to have a heart attack. He will now need to be on medication for the rest of his life.
I share this because he simply thought he had over-stressed himself - never did he think it would be something so serious. Your heart is nothing to take chances with - the sooner you find out what is causing your symptoms, the better.