Kris I am addressing the sore back to ridecamp 
because I had a horse who had a sore back for years and thousands of 
miles.  I went through many vets, acupuncture, massage and chiro, gads of 
saddles, took riding lessons and tried to face the  guilt that I was doing 
something wrong.
 
It was at the ROC in Utah when a vet approached me 
and asked if I had a history of back problems.  She could tell that my 
horses jaw was out of alignment.  When she 
showed me how his upper and lower jaw did not meet properly.  This put 
pressure on the junction of the joint where his mandible, temporal and zygomatic 
bones meet. She stated that any "treatment" 
would provide only temporary relief, lasting for a few months.  I needed a 
orthodontic to realign his jaw. 
 
Within a month of treatment the sore back was gone 
and I never had the pr0oblem again.  Just take a minute and open his 
lips.  See if his teeth  are in alignment.  Place your fingers at 
the TMZ junction and see if he is sore in the area. It is so easy to notice once 
you look for it.  Wish you the best.  Pat