I have this too. Sometimes mine are so bad that I get lightheaded, it's pretty scary. I have seen 2 cardiologists and had EKG and heart monitors and they said they are harmless palpitaions and that they are common. They are supposedly caused by anxiety
or caffeine consumption. I also notice mine are much worse close to my period so I would assume that hormones also play a role in these palps. If you are still worried I would ask your doc for a holter monitor
to rule out anything serious, and EKG is pretty useless in diagnosing arrhythmia
unless it actually does it during the test.