involuntary muscle movements at rest

My son just turned 6 and has been on the more active side. We just attributed this to his being a boy. He does well in school. He is up to date with his motor development. A little delayed in speech and has slight stuttering problem. He is very sociable and does not seems to have any problems interacting with other kids. He is on the sensitive side and cries quite easily if he doesn't get his way.

We noticed however 2 days ago while he was watching tv or at rest he started to have jerky movements in his right arm and legs with grimacing in the face towards the right. It does not have any definite pattern and he seems to not noticed the movements. Sometimes its not too bad and its just his arm making some small jerking. We are so worried. I took a video so that we can show it to his doctor.

I was hoping I could show them to you as I can't put them exactly into words.

Thanks you.