i ve been having tightness in my chest for the past 36 hours that has not let up( i woke up with this pain ) on the left side along with rapid heart rate( i m able to feel my heart beating through my chest and it s painful ) i can breath fine but I am being forced to take shallow breaths because if I try to breath normally or slowly and deeply the exhaling will cause extreme shooting and stabbing pain in the left side of my chest along with heart palpitations that are painful and can be felt in my sternum. neither of these areas are tender to the touch. what makes this extremely uncomfortable is that the symptoms get worse and worrying when I am at rest or with very minimal activity. laying down is when the worst pain occurs making sleep impossible. i am a 14 year old girl at an average weight with no drug or alcohol abuse prior to this happening. is this a serious concern that needs medical attention?