M here after long time. M having chest pain in my left side . It's start just few days ago. What is the reason. I hav ms n am on avonex, should I go to doctor? I search in google and found it that many people with ms have this problem. I found also that potassium vitamin is good. But I wanna listen from u guys, really m worry. Can I get heart attack? Pain is not more but it's hurt when takin breath , eating time, while laughing. Any body has this same problem? Thanks in advance for reply...