Following are the causes considered for the muscle twitching;
1) Idiopathic or benign twitching; as in facial muscle or eyelids. Any twitching which comes and go is benign and not due to disease process
3) Excess caffeine consumption
4) Deficiency of calcium or magnesium
5) Vitamin B1, B6, B12 deficiency
6) Medications like estrogen
Please read this resource for the further details;
Please feel free for your follow up questions.