Jamy-
So have you have MRIs or very detailed xrays?

did you get to look at them yourself?

did chiro see them? or take new ones?

I guess I don't understand the TOS comes and goes part????
The Dr is saying that? both of them?

I guess for some it is constant and for some {like me} symptoms will wax and wane.
It all depends on the amount and the cause of the damage for each of us. IMO.

your questions-
1) Has anyone had any success with accu. or chiro?

Yes I did/ still do , took about 3 months to get out of the spasms and constant tightness {2x at first a week then as better 1x a week and so on til once a month now}
I also had some long term misalignment issues {hips, ribs, shoulders and neck} and since TOS/RSI/CMP are pretty much chronic conditions I plan to keep going.
It's not a case where just a few adjustments will "fix" you - very rare if that happens.
i guess hypermobility would figure into the mix there - I have hypermoblie joints to some extent. Just hopping off the back of a tailgate and landing wrong will cause hips/low back to change and need readjustment. It doesn't hurt but I feel like I'm walking tilted- LOL.
Cost-
Mine did accept a lower fee - ins didn't cover and chronic case & maybe just a nice chiro.. .{ if fee/ cost is an issue ask about a discount}
approx fees in my area of USA about 50.00 per visit {I pay half that}

2) Any warnings off what not to do? What to watch out for?

If they do the "flying " adj {when they grab you and do a bunch adjs real fast} NOT GOOD

You want gentle precise adjustments and it's a bonus if they do other therapies for you - low level laser, ultrasound, Nimmo, c1/c2 adj, ect.

if you don't feel like a certain DC is helping - try another one- ask around and find an expert.