It sounds like you've rather bypassed the vet and that is where you need to go. Chiropractors and farriers unless they are also licensed veterinarians have a very limited education in anatomy and physiology and by no means are a substitute for a vet in diagnosing problems. This is not to say that they can't be of great help in treating a problem, but they can only assess based upon their limited knowledge of the body as a whole. In other words, one can only find a problem if he knows that that sort of problem exists and how it presents itself.
A good lameness exam to pinpoint the source of the pain would be the first step and then once you and your vet have an idea of where in the body the problem stems from you can discuss what kind of diagnostics and treatment would be appropriate.
Licensed Veterinary Technician