I Was Injured In A Car Accident A Year Ago.

I was injured in a car accident a year ago. My arm and shoulder healed. But my neck and between my shoulders are still giving me grief. The neck hurts bad when I try to move it back and forth. I also get very bad headaches at the base of my skull by the back of my neck. I've had PT. Am currently seeing a DO for osteopathic manipulative therapy and a doctor for trigger point injections. I get temporary relief. Then everything bunches up in a few days. What's causing the bad headaches that make me cry?