I have that vibrating feeling also. I was told it was a "silent migraine" symptom. I get it on my upper legs (and at first I attributed it to my phone as well) and sometimes in various other places.

I also get twiches in my hands that I was told were the same thing. Usually they are hardly noticable, but once I was holding a knife when I had a twich and cut my finger instead of the meat I was to be cutting.

In general, I think my nervous system has some serious problems and I haven't complained enough to a doctor to get any real answer.

If you find out more, please let me know.