SouthernMoss, I really should make an account. My mom doesn't really use this one though, so I wonder if there is some way just to change my username.
Seymour, considering your pain has increased, I bet your rheumatologist will monitor you carefully. You also have to remember that AS is a SLOW disease. It takes years to fuse. My SI joints have been fusing for 6 years. Since I have been on biologics that whole time, they haven't fully fused.
In early studies, they thought biologics did not prevent disease progression. Later they realized that those studies were too short - only two years long. So it looked like biologics were not preventing progression and might even be increasing it. But when they looked at studies that went for 5-10 years, the effects of biologics were MUCH more clear. They very clearly reduced the odds of progression by 50% or so.
My point is really that you won't fuse overnight. Especially considering you are on a biologic. I would really push for an MRI of your neck simply for your peace of mind. It will show if there is inflammation and how much (if there is inflammation at all). Pain can come from many sources. Nobody here is denying that you are in pain - clearly you are. All we are saying is that it may not be AS, and even if it is AS, it's better not to freak out! The pain is REAL - whether it is muscular, anxiety related, inflammatory or simply postural.
Losing ROM does not necessarily mean you are fusing. It could simply mean you have very tight muscles. With my neck, I have also lost ROM but my PT thinks it's because my trapezius muscles are so tight. He expects my ROM to increase as I continue with PT.
I agree with SouthernMoss about taking an NSAID regularly. There are LOTS of NSAIDs and I had to try about 12 before I found the right one. Celebrex is known to be easiest on the stomach. Mobic is also used a lot. I take my NSAID with a PPI - if I don't, I get gastritis. For me, dealing with gastritis periodically is worth it for the pain relief I get with NSAIDs.