1. Do you ground mount or use a mounting block? (the reason I ask this is because I am not a big fan of ground mounting unless you are GOOD at it and light enough- when you ground mount you are pulling the saddle over and it can pinch or displace the "properly placed" saddle)
2. Have you tried a Chiropractor? (please make sure you use an equine one- I would suggest asking your vet to recommend one)
3. Are you using too many or not enough pads?
Just some ideas