Hemifacial spasm (HFS) is a neurological disorder manifested by twitching on one side of the face due to involuntary contractions of the eyelid and other facial muscles. It usually begins gradually ...

you've experienced a muscle spasm, also referred to as a charley horse. These spasms, often felt in areas like the neck, legs ...

This article explains how tight neck, shoulder and upper back muscles ... by forcing these muscles to knot up. This results in muscle spasms. But despite these spasms, some tearing does occur ...

These common causes of muscle spasms are usually minor conditions that easily resolve. But you should talk with your doctor if you suspect a medication is causing your muscle twitching.