Well first thing to know is not to look on-line for the answer, because you will just freak yourself out more. I would just go see a doctor and ask them what they think. It could just be a congetive heart defect which is passed down from family. There is more fear in the unknown then the known. Once you figure out what you do or don't have you'll feel much better. Have you had any panic attacks?
I don't know about the thyroid
thing, but what about a heart valve problem (congetive). Mine is the mitral valve prolapse
, so I know a little about palpitations and murmurs
. I'm 24. so age doesn't matter.