Hi Jane,
My name is Dave, and I had ACDF on c/5-6 and 6-7 in February of 2007. I had great success with mine but now am having similar symptoms as you. Mine are facial numbness/tingling, arm pain and numbness, cold fingers and some tremors as well. Just had an MRI, and everything with the previous double fusion looks good. My doctor saiid that sometimes after fusion the discs above and below take additional stress, and are more susceptible to degenerative issues. It appears to be my case as c/3-4 is now bulging.
So, I think it could most likely be your neck, although I am not sure as I am not a doctor. Based on my experiences though I think it's a good bet. As for surgery? I am not sure if they would recommend it or not...probably depends on how bad this affects you. I will post here after my appointment with neuro surgery and let you know what they recommend for me as it sounds like we may be in the same boat!
If you want to contact me with questions, feel free.
Dave