Yes,I do this. Even a soft touch on my arm can elicit a,startle reflex and the pvcs. All I can say is I hate it. It seems worse in the mornings for me but happens any time.
Loud radio, tv, make me jumpy since I started having irregular beats. It doesn't take much. I, too, think maybe it's an adrenaline surge. As the day goes on and my beta blocker kicks in, I am usually calmer. I also have a really good "startle" relflex.
Is it possible you are easily startled? Some poeple are just more jumpy and the adrenaline can cause them, but obviously you should make sure your palps are benign.