I would head for at least urgent care if not the ER. I really don't know what's wrong with you- maybe one of the doctors on this forum will weigh in but I think you should be seen!
They might want to check you for spinal meningitis with your spine and headache symptoms.
They might want to check your blood flow to your brain.
Whenever you have a severe headache when you've never had one before, they generally want to do a brain scan to check for tumors, etc..
Also, do you have your appendix?
The cold right arm and hand sounds like there may be a nerve component to the equasion.
Hoping a doctor on the forum will shed some light for you.