Back And Neck Pain For Days

A couple of days ago I woke up and felt like I had a crick (sp?) in my neck. As the day went on it seemed to worsen instead of get better. Yesterday morning when I woke up it seemed worse. The pain was down into my shoulders and instead of just hurting when I would turn my head one way, it started hurting to move my arms also. This morning when I woke up the pain was more intense and encompassed my neck, both shoulders and seemed to have spread halfway down my back. It is painful to move my head forward, backwards and side to side. It is extremely painful to raise my arms above my shoulders. Any ideas what could be the reason for this and why it isn't getting any better? I've been sleeping on the same bed and same pillows for two years now, I haven't been carrying heavy loads or moving furniture or anything that would strain my muscles. I am not sick, no fever, and no pain anywhere else in my body. I really am clueless as to what could have caused this pain to last for so long. Normally if I sleep on the wrong side and get a crick in my neck its gone by the next day. This seems to be getting progressively worse.