This doesn't happen to me very often. In fact, hardly ever. But I know I've seen people here talk about it. I had a six-hour drive today (which turned into 7 because I caught traffic at the end). I listened to music and audio books. Had water. Stopped for lunch and snack and rest stops. At the end of my trip (because I am without my husband or son) I visited a bookstore for about an hour. When I came out and sat down in the car I realized my whole body was buzzing like crazy -- like someone stuck cell phones set on vibrate all over my body. I thought it might be that I'd waited a little too long to get dinner. Or that I'd forgotten my morning meds, but I hadn't. I got dinner, but it still hasn't stopped. It's been about five or six hours now, but it's still going strong. Has anyone figured out what causes this? It's really weird.