Sci

Ive been having a problem lately with muscle twitches and trembles. I notice them most Im resting, like sitting in class, or laying down and reading/watching tv. And they seem even more frequent in the evening. They can be anywhere from small twitches in my fingers to large twitched in my lep/hip that are extremely noticable, or in my back causing me to almost jump back in my chair. Also ive been trembling alot lately too, throughout my entire body. I cant hold my hand out perfectly still, sometimes I even find it hard to control a computer mouse. They feel like the trembles I get when I drink way too much caffeine, but the thing is I have hardly had any caffiene lately. Usually just one green tea in the morning.

Ive read a bit on what it could be, but there are soo many causes I just dont know, and its not really bad enough to be interfereing with my daily routine, but bad enough for me to notice. So what are the most common causes for twitches/trembles like that?

One possible explanation that I saw was poor diet.. If that is my problem, what kind of vitamins/minerals will help this go away? (Living in college res, off of cafeteria food, so not much choice)

*Another thing I should mention. This may sound kind of wierd, but.. when I get an impulse to do something (like scratch, or move or something) I will automatically have a large twitch.. even though I have not conciously told myself to get up, or scratch an itch. Like..
For exaple.. Ill have the idea to change the channel, instantly my leg will twitch as if it were to get up, but I didnt conciously decide to get up and change the channel yet... Sounds wierd, but thats the best way I can describe it =\