This neck pain may be due to spasm in lower neck muscles associated with some irritation of nerves in spinal cord..
Next Steps
Walking can be done but there is a possibility of increase in pain if spasm is significant. So it would be better if you avoid walking for long duration till the pain subsides.. You may go for hot fomentation, take analgesic tablet, apply analgesic ointment locally
Health Tips
Avoid any jerky movements of neck, avoid heavy work..