If my 24hr ecg is normal and i'm still experiencing palpitations what could it be? also i did thyroid test and it is still good.

It could be : Psychological, stress, anxiety or it's real caused by what u drink - too much caffeine from soda or energy drinks etc. Get checked for pheochromocytoma. Ask your dr if he would consider giving u beta blockers. Read our website's tips on anxiety. Take care and god bless u:).

Maybe Holter monitor: Sometimes patients can wear event monitors or holter monitors for a while to try to capture events that don't occur during the "snapshot" of an ecg. Should the palpitations continue sometimes medicines like beta blockers are used.

Look further: Normal ekg and echo are not enough to dismiss your symptoms. You need to explore further. A session of multifunction cardiogram may help! http://en.M.Wikipedia.Org/wiki/multifunction_cardiogram.