OMG! Help MeH! sOmething like A heart disorder I think?

I cannot move my body, only my fingers. And it is happening right now. I also can't hardly breathe that deep. I can only take small breathes because If I breathe normally or deeply, my heart hurts! even if I will just move my body! What to do?! It happens to me all the time, but this time, it's worse! My body have to be in the right posture, like I have to sit straight, chest out, stomach in! like that! because if I slouch my heart would feel pain! what to do?!I can't take it anymore, I think I'm gonna die!