I had three disks fused in my neck about a year ago, but I still am having pain across my sholders and in my upper arns. Is this normal?

Needs eval. Persistent pain neck pain and upper back or upper arm pain may indicate a problem such as a failure of fusion or a new disk problem at another level. This is especially true if the pain is progressively getting worse. Some patients experience these symptoms even if there is no problem with the prior fusion or another problem elsewhere in the cervical spine.
Yes. Having a surgery in your neck never guarantee pain free life. The arthritis if that was the cause of your surgery, remains and still causes pain. Now that the surgery occurred, scar tissue also developed that is causing some of the discomfort as well.