Count me as one who has a lot of experience (40 years) taking NSAID's and they have made my AS easier to live with. Whether you call it a "treatment" or "pain management" to me is irrelevant, what is important is that it helps. I do not have a "mild case" as my spinal column is 100% fused top to bottom yet at 58 I still am working, playing golf and all things considered doing OK. The important thing is finding one that works for you and your stomach can handle. I had to try several and have been taking flurbuprophen for quite a while. It's not the strongest, newest or even the most effective but I can tolerate it long term which is important. It will take some trial and error to find the right one for you but my experience is they definitely help.
Best of luck.