Hi Ted: I'm sorry your having such a hard time. I've never had a cervical fusion but have had many lumbar and the pain was always worse after the surgery. With me I never got immediate relief from the pre-op pain, and when you add the surgical pain to that it was usually double the intensity for that reason. I also had times when pre-op I had No left leg pain, just right leg, then after the surgery had pain in both.
Basically I was told the same thing as you that the nerves were moved around a lot, muscles and superficial nerves were cut so all that has to heal and will cause pain that you never had before. I know a lot of people who get immediate relief in pain, to a certain extent, but it didn't happen that way for me. Slowly I got better and the pain lessened but it took quite a bit of time.
I would stay on top of the pain, telling your dr what's going on, and figure he is right that it will subside in time. I don't know how much nerve damage you have, but if you have some that takes a while to feel better.