What Causes Muscle Spasms Below The Neck?

I have been getting these what I think are muscle spasms on the left side of my neck right below my ear. They just started today and are extremely painful. The area is tender to the touch as well. There has been no injury to the area. The pain is severe and sudden. When I get the spasm the pain shoots down the side of my neck. Is this something I should be concerned about?