First of all, you don't describe typical heart-type chest pain. You may be experiencing some other heart issue such as an re-entrant type of rhythm, you may just have lungs hurting, you may be having an allergic reaction.

Obviously, you need to stay away from MJ. Interesting that cigarettes do not cause this....that says much....go talk to your doctor about this. My concern would be the elevation of the heart rate. Many reasons for that. MJ itself should not cause direct heart issue. Heck I had a 99% blockage in the left artery branch of my heart and kept using throughout without ill effect.