i'm fortunate enough to have started twitching before google was a thing. my muscles started twitching when i was a teenager, mostly little muscles all over my body, often in my forearms, sometimes eyebrows, thigh muscles, fingers etc. just like those muscles would contract and release very rapidly for a period of maybe a half hour at a time? happened all the time, and because i was experiencing bad anxiety but NOT health anxiety yet i just put them down to muscle tension, which is of course what they probably were. still happens a fair bit but i barely notice. or i say to my wife HEY LOOK WHAT MY ARM IS DOING!!