When I am relaxing (just before sleep, watching a movie, etc) I get very violent spasms in my left arm (like mini seizures), and sometimes they also affect my neck so that my entire left size will suddenly jerk. I am not sleeping when this occurs, and sometimes I am not even trying to sleep--just being still. I have even punched myself in the face doing this. I also know what myoclonic jerk feels like and this is not it. I would really like to know if this is serious, and if there is any treatment.