sorry i have left a message but not sure where it ended lol.what i said bout the stifle joint problem i have got 2 stress incase someone else reads is that it isnt easy and you must study how its to be done and have 110% confidence or know someone who is very capable and this is why i stress so much to people how important insurance is

I'm afraid i'm on the wary side too. I had a chiro to my mare a couple of years ago, just for a general checkup. She found loads wrong with her, treated her and it went downhill from there and it was one thing after another, she treated her and put stuff out that wasn't out in the first place! I ended up having a vet out to get painkillers and then had a physio out. I've never looked back and have the physio out every 6 months now, she knows my horse now, works closely with our vets and won't treat unless needed.
I'd get a second opinion.

I have had brilliant results from a trusted 'back lady', quite often the rescues that I take on have back problems, some I can fix myself and others need her help. Quite often it is from the wild ones rearing and going over backwards, hurling themselves into walls, other times it is a big buck, an accident or rolling awkwardly and getting cast. The spine of the horse is slung between both sets of legs and it does get problems. But first like has already been said check the tack! Saddles are the worst culprit then bits. If in doubt try lunging and riding bareback and see if the problem is still there. Hard to do if its outdoor napping though so stay safe.

But there are many quacks that charge the earth and do nothing so be wary and go on a good reputation