Holy moly. I have experienced the same thing. I keep my cell phone in one of two pockets - my left hip pocket, or the cargo pocket just above my right knee. I have muscle twitches in both of those areas, but only when my cellphone is in the pocket near the area.
Even weirder - yesterday at work, we had a temp worker in helping us out. He was standing 7-8 feet away from me, and his cell phone rang. It rang 2 times before he answered, and each time it rang, my right hip started twitching and pinching something fierce. It hurt!!
I wish I had something else to add, aside from my own anecdotal evidence of what we all have experienced.