I just realised recently that my twitching all but vanished and the buzzing almost completely stopped when I switched from working on my laptop (always sitting on my legs) to a desktop computer. I wonder if the electric stuff sitting a pulsating on your body could contribute. I know it sounds far fetched... but worth asking. I know all of us spend time on computers because we've all done the google-our-symptoms-to-death thing. Try it out!