I'm sorry you are struggling so much and are in so much pain. I too get neck-related headaches and I can completely identify with your comment that they are like no other headache!
As to whether they might be potentially RA related, my experience is that it is really not always easy to identify the cause/source of the pain. I have had RA for many years and I suspect that I do now have some degeneration of the joints in the neck, but I also think that, in my case, the underlying cause of my neck-related headaches is the problems I have with my shoulders. I know that when my shoulders are giving me trouble, I tend to tense up and this can affect the muscles in my shoulders, neck, ribs and back so it's actually very difficult to pinpoint the source of the problem. You mention problems with your jaw so that could also be having an effect.
It is also easy to underestimate the effect of "referred" pain, caused by walking "carefully" on sore feet, knees etc. I remember, in the early days, having tremendous pain in my hips and being convinced that my hips were affected by the RA. But the consultant told me that he thought it was down to the way I was walking putting undue stress on my hips and that he thought it would ease once the RA was under better control and I could walk more easily. And he was absolutely right.
When you have RA (or potential RA) it is easy to assume that everything is RA related and it can be very hard to "see the wood for the trees" MAGSWAT. I really do hope that, when you see the consultant, you can start to get some answers - and some help.
Thinking of you.