Hi Misty!
This sounds a lot like what happened to me. Prior to diagnosis I had an MRI done. The MRI was negative as was all my lab work, with the exception of being HLA-B27 positive. I saw a rheumatologist and she told me it was "highly unlikely" I had AS for a multitude of reasons and pretty much blew me off. Three weeks later I saw a spine specialist and he did an x-ray on my pelvic area and low and behold there were changes, but very minor ones. That day in particular though, my pain was so bad I was trembling from head to toe. Long story short I found a new rheumatologist who looked at ALL my imaging and confirmed I did in fact have AS. My lab work is consistently negative though. Are you on any type of treatment plan?
-Katie