Your symptoms are very common. I have had PVCs for years. At least since I was 16, but probably longer. I'm 42 now. When I was a teenager, I often had heart palpitations. Then over time I would feel an occasional thud which would nearly scare the crap out of me. As time went on, I felt them more and more. I finally went for a full work-up and was told they were benign. On a good day, I had 100 PVCs, on a bad day 24,000!
I will tell you that anxiety is a huge cause of PVCs. Also, if I am stressed, over tired, angry, they increase. Last year, I had a bad bout and decided to drive myself to the ER. I was having about 40 PVCs a minute and non-sustained V-tach. Since then, I have had multiple ekgs, an echocardiogram, a holter moniter, stress test, cardiac mri and tons of blood work. I have been told, they are benign and that my heart is structurally normal. You and I happen to be the unfortunate ones that feel them.
Occasionally, although I think I am used to them, I feel like flutters or vibrations. It just feels different. I try to just talk myself through the episode and breathe. This could be short runs of v-tach. This may be what you are describing.
Exercise could decrease the PVCs and I encourage you to get as much exercise as you can. Take a walk, ride your bike, swim. It will be good for your heart. Don't be surprised though if after you exercise, they come right back. This is very common and nothing to be afraid of.
As for supplements, I have tried them all. I take magnesium. For me, if I feel like the PVCS are getting unbearable, I take CoQ10. This seems to lessen the intensity of them and helps to relax me.
Here is an article you may want to read about supplements.
Hang in there. I hope you feel at ease!
I don't care what anyone tells you or what you read from studies sponsored by the coffee industry. No caffiene, none, zip. Stay hydrated, drink plenty of water. Avoid high carb crap like soda, pop, sugary stuff.