If I have severe neck pain does that mean it's a pitch nerve?

Not always. There are many causes of neck pain, even severe neck pain. They include pinched nerves, arthritis in the neck, poor posture, fractures, muscle pain as well as more serious causes such as spinal cord compression, tumors etc. Most neck pain is benign, meaning it will not kill you but it can certainly ruin your quality of life. See your doctor and if you do not have one try to find a doctor.
Possibly. Having a pinched nerve in the neck can cause neck pain, headaches, and pain or numbness that runs into the arm and hand. That being said, there are many potential causes of neck pain from muscular, inflammatory, or spinal causes. I would encourage you to schedule an exam which can usually tell the cause. Thank you for your question.