Open Question: Why do I spaz out in my sleep?

At the time, I went back to those who belong to my hands balled into fists at the top and fell asleep. I turned the whole night, but no matter I was in my arms / hands to sleep. I shook my bed and shake my legs and feet sometimes. My boyfriend said that I grind my teeth very well, sometimes do, I'm in my sleep. I whipped my head around, and sometimes even hit his head really hard. I will wake up in the morning, do not remember it all. Also my wrists and hands started to pain me how much sleep, but I can not sleep any other way! Why I do what I sleep all these stupid things! ?