Chest pain

My heart has always been a little weird, it'll flutter, sometimes I'll get chest pain, I've mentioned these things to my doctor and she usually just dismisses it. She's never been worried since I'm only 22. But today, the whole left side of my chest and my left arm are hurting pretty consistently. It's a stabbing pain in my heart that moves down my shoulder and arm. Should I be concerned? At what point do I insist that there's a problem??