If i look over my left shoulder the left side of my neck cramps up and i feel pain in my neck and my head shooting up. what can it be?

Muscular...: If you have not suffered any injuries this is most likely related to a muscle spasm. Ice and anti-inflammatory meds(like ibuprofen) should help with symptoms. If you have suffered recent head or neck injury go to the nearest urgent care center for evaluation.

Muscle strain/spasm: you should be examiimined; however this sound like a muscle spasm. I suggest the immediate use of Advil or Aleve (naproxen) ( if not allergic) PLUS eith ben-Gay, local heat or my preference: BioFreeze, until you can be seen or evaluated. If symtoms worsen or associated with nausea.vomiting-go to a UC clinc or ER. Call for an appointment ASAP.