Over the past week, my neck s range of motion has decreased, especially to my left. Occasionally, if I glance to the left, my neck locks up and I get a rocketing vertical pain into my skull and down my upper back.Sometimes my vision blacks out for a split second. A few days ago I was lying on my back. When I slowly moved to sit up, swinging my legs to the floor my upper body and arms began flailing as though I was having a convulsion. What the heck happened? Should I see a doctor?