Have you had EMG (nerve conduction) studies?
Did the leg/foot troubles happen immediately after the surgery? Does the foot "drop" or is it any movement that is hard?
I can't diagnose this over the computer; but i'm very suspicious about the neck surgery. You should ask your surgeon if he messed up, or seek a second opinion and get a lawyer. Certainly get a second opinion from a neurosurgeon.
The leg symptoms are not normal following neck fusion. Best of luck to you.
Unfortunately, the computer just erased my answer, so I have to start again.
As mentioned above, a second opinion is important here to ensure that there isn't anything surgically correctable here.
While your neurologist is correct in saying that much of this probably is unfortunately permanent without any fix - some of your symptoms, such as the left arm pains when your neck is bent forward could be potentially correctable.
Other symptoms, such as the numbness, burning, and weakness on one side seem to best fit with possible spinal cord injury, and the fact your numbness starts in the upper chest seems to fit with a lower cervical spine injury.
So, it is important to get your old hospital records, including operative notes and operation records, and get this second opinion.
The Hospital for Special Surgery primarily is Orthopedic surgeons who perform spine surgery, but has a very good reputation when it comes to spine surgery: