slow heartbeat

I'am 20 years old and have a heart problem, whereas although I have been to doctors in the past and recently no one has given me straight answers.  I have a slow heartbeat, and in situations where I get angry, upset or stress myself I get really bad heart pain, as if so ... [More] meone is stabbing a knife in my heart, I have difficulty breathing, in the past in a situation where I was arguing with someone the pain started and I fainted, this has only happened once, please can you tell me the reasons to my situation, treatment for it and its dangers.

[Jerry_NJ]

We would have a better idea on how to comment if we had some number and facts:
1) what is your normal and slow HR?
2) what is your normal BP?
3) avoid anger, this may be hard but if your work on it I'm sure you will reduce the number of times you almost pass out from arguing.    One suggestion, don't feel you have to "win" an argument, just make your points and if they are rejected move on and let the "opponent" know you don't agree with them but see no benefit in additional discussion.

[NTB]

you might look at coronary artery spasm, aka Prinzmetal  aka variant angina

or vasovagal episode

or maybe sick sinus syndrome or some sort of heart block

(just some ideas)