I had a whole bunch of months a few years ago where I had
benign early beats (PVCs). They were alarming and really annoying and kept me up at night. They were also completely harmless.
My GP sent me to a cardiologist and I wore a Holter monitor. I had a stress test and an echocardiogram. There was nothing wrong with my heart.
The common causes for these kinds of things are too much caffeine or alcohol. I had neither of these. Ultimately I concluded that my PVCs were probably related to asthma flares related to seasonal allergies.