Could it be that you're getting a reaction from something you're taking with the lithium? Motrin or ibuprofin when taken with lithium can cause those side effects. In fact, sometimes it seems that everything else I try to take, whether prescribed of over the counter, can cause those side effects.
Have you ever taken zyprexa or haldol? Even taking them for a short time can cause a neurological disorder called Tardyve Diskenesia. Sometime is doesn't make itself apparent for years after stopping the drugs, and therefore is overlooked as the culprit. I'm one of the victims. There is no cure and no treatment. It causes tics, most commonly facial twitches. As for myself, I have a raging case of restless legs, and I also bob my head and move my torso, especially when I'm agitated or excited.
You may want to get the Pill Book and look up each of the meds you take to see if there's a reaction.