My chest is hurting here and there and also when I take deep breaths, I checked my heart rate and it's 126. will I be OK?

Yes - if this is caused by anxiety and heat. If its caused by something else, doc probably would have noticed anything dangerous in past check-ups. There's not many heart problems that occur in teenagers.

you just need a quality vitamin/mineral combo, cuz the foods no longer have them like they used to

Chest pain in teens is pretty common, almost always anxiety or gas.
Heart disease are in the old, over 60 years old. Very rare in kids.