Hey PinkGirly, Welcome to Healing Well forum, we are glad to have you join us here.
Keeping in mind that we are not here to diagnose you and you should seek medical treatment if this has been occurring for as long as you state here. Now, you have several advantages on your side here...one being that your young, and it could be anything other than a heart problem...such as an increased blood pressure (which should be checked by doctor) or gastric problems which are often mistaken for cardiac in the beginning.
If you do have a family history of heart problems/disease then of course that would have to be considered. In my opinion though I would be getting to the doctor to get checked out. I forgot to leave this link for you too...I thought perhaps it might be of some use to you...