Dogen

Is the muscle twitching, or is it merely the sensation without any movement of the muscle? A muscle twitch would be more suggestive of electrolytes. Sensory perception without muscle movement would suggest something else.
I've had this before, but only experience it on the left where I keep my phone, which is always in vibrate mode. I've always assumed it was a sort of sensory aftershock. Nerves that are stimulated frequently can become sensitized to stimuli and may trigger a sensation more easily (similar to central sensitization in chronic pain). So, I think my left thigh sensory neurons get triggered more easily because they're primed to feel the vibration of my phone, and now they trigger over the slightest provocation whether my phone is in my pocket or not. This actually sounds exactly like what one of the articles Risk Manager posted talks about, where resident and attending physicians reported increased phantom vibrations in the location of their pagers.