Hi Liz, welcome to KA! I am so glad that you found us and hope that being a part of this wonderful community will prove to be a big help to you.
That is a terribly long time to live with AS, not knowing what on earth was so wrong. I'm so sorry you had to suffer so long without any answer.
Hopefully now that you'll be getting in to see a rheumatologist, you will receive much better care and far more appropriate treatment. Advice or referral to a physiotherapist that knows AS may be really worthwhile; you are absolutely right that exercises tailored to your individual situation should really help. Very gentle stretching exercises I can manage but if I over do it, it will make everything worse for me too and only exacerbates the degree of inflammation which is the opposite of what we want. I was advised by a good physio that if my pain increased longer than 2-3 hrs after exercising then I should take that as a sign I was doing too much.
I can relate to the stiffness and neck pain, and know that horrible vice-grip band of pressure around the rib cage. I hate it! Inflammation causes fatigue which is a common feature of AS for most of us.
There are some effective treatments now a days, although it can be a journey in itself to figure out what works for you, but hopefully things should really start to improve for you soon.

Glad you won't have to feel so alone with this any more, nice to have you with us!
mig