Why i can't move my neck without pain.

Many possibilities: Needs rapid examination by a doctor licensed in your area. Not enough information here but if you are unwell/feverish or limb weakness/numbness then nasties such as meningitis or other serious neurological conditions need to be rapidly excluded. Other less serious possibilities include viral illness and neck muscle spasm. Please get examined urgently at your nearest urgent care facility.

Well: Firstly you have to give a good history of the neck pain. Did you have an injury? You need to give more information. Best thing to do is to see a doctor for evaluation of the neck