I have to say it could be many things in my opinion but what you should do is go seek a doctor as soon as possible. It could be a neurological issue or what the person said above me but you will know the right reason until you see a Dr and have him wrote and order for a CT or an MRI done. I hope you feel better.
HI,Sorry about that.
You possibly suffer from occiptal nerves inflammation due to tension neck pain,which can lead to headache,numbness in face ,,,etc. you should go to see doctor.