Is an eye twitch something to be concerned about or is it fairly common?

Fairly common. An eyelid twitch (also called blepharospasm) is often due to stress, lack of sleep, or too much caffeine. Anything irritating your eye can also cause the twitch, so if it persists, or if you experience any other abnormal symptoms, follow up with your local ophthalmologist.
Common and benign. Dont worry... It almost never is anything serious. Usually the twitch will go away in a few weeks. If both the upper and lower lids spasm, or if the spasm spreads to the entire side of the face, i would consult your doctor.