hello,
you experience PVCs ... some I get are like what you describe.
it is uncomfortable, but if you have been tested and cleared by doctors, you should not worry. some of mine are intense, they thud, thump, flip, they run wild, they roll over....all of these weird wild sensations....very scary and annoying....it is a helpless feeling, disruptive. just hang in there....they will eventually let up..
God Bless