Stress? Chest pains...?

I am a 3rd grade teacher. They're behavior is terrible!! I have to teach and raise them. I have been having chest pains for the last 3 weeks. It started after I yelled at them one day. I think I might have pulled something. Do I need a new profession? I do not have any other previous conditions and I am 27. ---Do not respond saying I should not be yelling at them Until you come sit in a class with 32 kids alone, who act like heathens, you will not understand that part-- Thank you.