Hello and thank you for your question. Welcome to the forum. Here is an older question with a great answer by one of our members that may help you understand what is going on. https://www.medhelp.org/posts/Heart-Rhythm/Are-PVCs-normal-and-are-palpitations-and-pvcs-the-same-thing/show/1396372. It
sounds like you are familiar with PVC's? People of any age can have them briefly and they can't find any other reason for why while others may have longer periods of them and have an underlying situation occurring such as heart disease, injury to the heart or other non cardiac reasons. For our readers, here's some information on them. https://my.clevelandclinic.org/health/diseases/17381-premature-ventricular-contractions.
Palpitations are also very common and normally not serious or harmful. Things like too much caffeine, stress and anxiety, different medications people take, hormonal fluctuations as well as other things can lead to them. https://www.webmd.com/heart-disease/guide/what-causes-heart-palpitations#1
It's best to be checked out by a physician, of course, and get their guidance. And if you have chest pain or shortness of breath, please go straight to an ER for assessment.