Palpitations is a very vague term. Many, if not most, people have some irregular beats during the day, most frequent premature ventricular contractures
(PVC's). Hardly anyone is even aware that these are happening, though some people complain of a momentary "empty" feeling followed by a very brief period of forceful heartbeat. Several abnormal heartbeats in a row may be a sign of a problem, though evaluation often reveals nothing amiss aside from the rhythm itself.
The normal workup involves an EKG, and possibly a Holter monitor
. The holter records the rhythm over a period of time, from 24 hours to as much as a week.
If these are abnormal, it may be necessary to do a heart cath, or an electrophysiology study. The EP study takes recording from inside the heart and can find oscure reasons for arrythmias that have been previously undiagnosed.
If you have arrythmias that you are consistently aware of, you need to be worked up. Many times it will be nothing, but may be serious, even at a young age.