The common, less serious causes of muscle twitching include: 1  exercise. 2  stress and anxiety. 3  caffeine and other stimulants. 4  nutritional deficiencies. 5  smoking. 6  irritation of the eyelids or surface of your eye. 7  reaction to drugs, such as corticosteroids, stimulants, and estrogen.his condition is fairly common, and symptoms usually go away after a couple of days. There are also less common and more serious causes of muscle twitching. These medical conditions and illnesses are often related to your nervous system. They may damage the nerves connected to your muscles, leading to twitching.