My neck started hurting yesterday and now I can't move my head. What is going on?

I woke up yesterday felling fine. After about an hour and a half in bed with my lap top my neck started hurting. It was mild at first, but got progressively worse throughout the day.My the time I got home from work last night I was unable to move my head due to the pain. I am currently laying in bed in excruciating pain. Please help!