Why do my muscles twitch?

I never go a day without one of my muscles twitching (and by twitch I mean slight contractions that could be compared to quivering). You can physically see it, and sometimes it gets REALLY annoying. It’s never any specific ones, but most often my quads, biceps, and calf muscles. I’ve even had the muscle behind my eyebrow twitch. Most of the time I try and think about something else but right now I’m trying to do homework and my right quad has been twitching for almost an hour straight. Is this something I should be be concerned with?? More importantly is there anything simple I can do to get it to stop?? I’ve heard people say things like start exercising or drink more milk but I don’t know if this happens to everyone or if there is something I’m doing to cause them to twitch so much.