Are you somehow laying on it (have it under your pillow, perhaps) and stopping the blood flow? What do you do for a living? If it's something that involves a repetitive hand motion (typing on a computer, for example), it could be a symptom of carpal tunnel syndrome.
The body keeps turning over in sleep. It is unlikely that 'pins and needles' would keep happening to the same part. A visit to the GP is in order. The carpal tunnel suggestion from Ouish is likely. My friend has just been through all that and it was overuse of her computer in a repetitive action way.
Pins and needles are a side effect of beta blockers. Check the side-effects list of any medication you're on. I agree with the others though - best have a word with a doc!
It might be the way you sleep, and your blood isnt circulating correctly so its causing the numbness. I wake up with sometimes a slight pain in my fingers, and I went to the doctor for it. They told me thats what its from, and you sound like you do the same thing as me.