Originally Posted by The Greener Side
Rode him last night and while he wasn't tossing, he's still bracing his head and hollowing his back, which I worked through, but took 20-40 minutes to get a nice headset!
stop worrying about headset and try trotting on a long rein and see his reaction. If the horse is reaching for contact, then he's loose, if not, keep trotting and bending until he is.
Then try the trotting exercise I just posted. Sounds to me like there is back stiffness and pain.