I found this old thread while searching for something else. I have SFN and I have this too when I try to sleep. Change in my diet, supplementation, exercise and sleeping in a timely manner all helped reduce and get rid of these for the most part. It still happen now and then, but rarely. The internal shaking when I'm lying down to sleep at night is the more common and almost nightly symptom, but that has calmed down mostly too.