Just had to share that I have had this happen to me over 15 years. It's like you describe feeling like a cell phone buzzing. I also describe like a little motor vibrating in my foot and (sometimes both!) It scared me when it first happen and it went on for months. I finally went to a neruo dr. and was put thru all the tests for ms and everything was fine. But the buzz persisted. After many months, I realized it was something I was ingesting. I finally figured out it was some supplements I was taking for weightloss (still not sure which ingredient it was) and also diet drinks with aspartame in them would make it start up.
I went many years avoiding any "new" supplements and still today always careful to test and observe. My holistic dr. put me on St. John's Wort a week ago for anxiety (gee, wonder why I'm on this site to begin with... :0 ) and sure enough the next day my left foot was buzzing off and on. It's more annoying than anything else, but realized there is something in St. John's Wort (which is weird because it's supposed to have a calming effect) Anyway, I stopped taking it and it took about 3 days to calm down. How crazy is that? People think I'm nuts when I tell them about my buzzing feet! Anyway that's my experience on it, but I also know I am very sensitive to stuff and my central nervous system seems to be wound a little to tight!