About a year ago I had neck fusion surgey since then the muscles in my neck constantly hurt is there anything I can do?

PT. You need physical therapy and continue to do the exercises at home religiously.
May need injections. When the spine is fused, the joints above and below the fusion become over burdened and over worked. They become inflammed and the arthritic changes are accelerated. The muscles may indeed be in spasm but probably triggered by the underlying pathology. Trigger point injections, facet joint injections above and below the fusion may help a lot. Must make sure you didnt herniate the discs above/below.