Something popped in my neck last night and now i can't move it without very severe pain to put my left arm down.

Possible disc: If you don't have a lot of arm weakness then try ibuprofen, moist heat to the neck, and consider a soft collar when you are up and about. Be patient as most of the time this will get better.

Consider...: ....Seeing a good chiropractor. With a problem like this, a *good* chiropractor can often make you feel better before you leave the office, instead of days later.

See a physician.: You probably have a cervical strain. You should consult your physician. Your symptoms are caused due to muscle spasm. Your physician can prescribe you some nonsteroidal anti-inflammatory medication and muscle relaxants and or physical therapy which will help to alleviate your pain.