Some back pain in your horse is obvious: he flinches when touched or groomed. There are other signs to watch out for:
Stiff or restricted movement
Dips the back when first mounted
Steps short with hind legs
Starts refusing jumps
Avoids trotting: wants to go directly from walk to canter.
Wants to use one canter lead no matter what direction is being traveled.
Swishes tail excessively during work.
Many problems with back pain can be corrected with different forms of massage, cold laser therapy, acupuncture, and saddle adjustments.