Vibrations in the chest which are not actually coming from the "skips" themselves are not uncommon. Most doctors are at a loss to explain them. I encountered them when my PACs showed up some years ago, with an occassional PAF event. They are typified by a thrumming sensation deep within the chest, near the heart, and occur whether you are having skips or not. It's difficult to actually feel them on the outside by touching, although at times you may be convinced that you should be able to. I can tell you that in my case they feel like I could be in AFib (because they feel like the top of the heart, the atria, are fluttering)...but there is no arrhythmia.
After a number of years of literature investigation and discussions with EPs and Cardios, the best hypothesis is that they stem from the foci that normally lead to arrhythmias. Foci are islands of active cardiac tissue that throw off those annoying electrical signals that get intercepted by your normal pacing pathways and cause the heart to beat prematurely. I think that some foci can be located close enough to a branch of a normal nerve (phrenic, or otherwise) for their signalling to be picked up and "felt". I also noticed that these vibes are most easily felt when you are nervous or excited...or if your are anxious. When your nervous system is tuned up, it acts to amplify those signals. Over the years I've calmed down, and the vibes are more difficult to notice.
No cure here...just a possible explanation.
These are tough situations. If they have tested your heart and GI tract and they are normal that is good. If you have the symptoms even when you are not having PVCs, they are not caused by the PVCs. In cases that we cannot find a cause for symptoms like this, I often recommend taking medications for anxiety. I can't tell you that it is definitely anxiety, but my feeling is that if a cause cannot be found it is worth trying to see if it helps.
I hope you find relief soon. Thanks for posting.