I've had heart palpatations before but just once in awhile but today it has lasted for acouple hours what could this mean i was at work n it jus starte?

Talk to your doc: Persistent palpitations may indicate a cardiac arrhythmia. Document your pulse during the palpitations (?Fast, ?Regular).Try to get an ECG while you are having palpitations, so a cardiac rhythm abnormality can be diagnosed. You may require a long term "cardiac monitor" for 1 month to detect this. At your age, persistent palpitations may be indicative of svt (supraventricular tachycardia).