Left shoulder and left arm pain

This past April I had surgery to repair 4-5 and 5-6 vertabras in my neck, when I woke up from surgery my left hand did not want to work correct, I lost all my strengh in my left arm from shoulder to hand. (I am left handed also) My forearm has been numb as my forefinger and thumb on my left arm are also numb and asleep since the surgery. I spoke to my nuro-surgeon about this and he said it should get better, so I figured I had to live with it. I started lifting a small weight to strengthen my arm. It got better, but my arm and hand still was numb, until about three weeks ago it happened again and I was not doing anything to hurt anything. The pain is so great that I just about can not stand it, I have went to the hospital emerency room for the pain, they gave me a pain shot that did not help much. I went to my orthopedic doctor he sent me for a MRI and said my neck was ok and then he sent me to a shoulder doctor and he said my shoulder was ok, but I have iratated a nerve. This pain starts in my upper shoulder goes through my shoulder dowm my bisep and my forearm and then to my left forefinger and my thumb. Pain medication helps, but does not stop it. I also lost the strengh in my arm again. It feel like I can rub the back of my shoulder where it hurts and I can feal the pain all the way down my arm to my hand. I think it is a nerve somewhere in my neck and shoulder area, as this had not happened until my neck surgery back in April. I also broke 2-3 in my upper neck in 1980. It keeps me awake at night also. I need help as to stop the pain.