13 and have throbbing heart pain for almost twenty four hours?

I'm 13 almost 14 and have had a couple episodes of a throbbing or slight pain in my chest not burning or anything. Yesterday I had physical activity on off for the whole day and on the way back home started getting the pains in my heart. For almost a day now I have had slight pressure and throbbing in my heart on off sometimes more severe than others. The past two nights I have been nauseous if that means anything. Any idea what it could be? I'm healthy and exercise a lot.
13 and have throbbing heart pain for almost twenty four hours?
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