Bizi...
I was thinking that in keeping with the thoughts of this book, why don't you read up on arthritis, do what you can on your own to see if you can get improvement and then set a date to see if that happens. Perhaps give yourself two or three weeks (probably no more). If you don't feel better...then "feel the fear and do it anyway" and simply go to the doctor. I wouldn't think twice about it....
I hope I didn't say anything out of line here. I haven't read this book in a long time. In fact, your posts have inspired me (thank you!) and I have re-ordered it used from Amazon! (I gave my old copy away a long time ago!). I think the bottom line might be that it is healthy and right to be responsible (this is a good thing) and part of responsibility is moving forward. Sometimes we have moments when this is a struggle, but in the end, pushing through these struggles and getting to the other side will make us feel better. During the struggle...just put one foot in front of the other...
Additionally, my guess is that if arthritis is paining you in both a physical way and in a psychological one (what I mean by this is that it is on your mind all the time and causing you to feel down, etc.), then it will be hard for you to full engage in the "process of life." You deserve better.
(Hugs)

p.s. Thank you also for that passage about the spiritual side of ourselves. This reminder was wonderful. Again, I do recall that this was a great book and do appreciate being reminded of this.