What Causes Severe Headache?

c5/c6 left paracentral disc osteophye complex with increasing thecal sac effacement and increasing mass effect. Can you please tell me if this is what is giving me ongoing bad headaches starting from my neck, bad enough to make you nautious. Also I have a locking in my neck that really hurts when I raise my arms or try to do things like my hair? Please help me understand. I am 51, very healthy, I was in a car accident were a tractor trailor backed into me on the hwy. I had c6/c7 fpost fusion with anterior plate and screw fixation through the c6 and c7 vertebral levels. Previously visualized large osteochondral bar at c6/c7 has shown interval resolution.