Twitching muscles are a sign of an irritated muscle. Sometimes gently rubbing the area to sooth it will help. Other times, the twitching can be a side effect of medication, stress or dehydration. Try masaging the area and make sure your drinking pleanty of water.
its probably a muscle spasm. muscle spasm are usaully caused by stress. Don't worry its nothing serious it will go away eventually. If it happens all the time and its seriously bugging you check with your doctor. Muscle twitching is an activation from the muscle fiber by a single firing of a motor neuron in your brain.