i am 17 years old, almost 18. I have a very fast heart rate as it was checked by my doctor and said i have resting tachycardia. I have been having chest discomfort and sometimes feel like my chest is really warm. a few days ago i had sharp pains under my left breast but haven't had it since that day. I have today realised that my left lower leg is ver slightly bigger than me right and feels warm at times. i get hot warm and cold flashes throughout the day. I also get mad really quickly and have severe mood swings. is there anything to be concerned about?