My horse is lame at the trot after pulling back while tied, I now use a tie ring that releases if he pulls back. Upon speaking with the veterinarian I believe that he pulled the shoulder out of socket because he was lame instantly and swinging his leg way out away from his body at a walk. I too have sought chiro and veterinary advice (my vet is qualified in both fields)
The vet adjusted him and then put him on b12 pellets which is a natural anti inflammatory and told me to ride him and strengthen him. She came back out after the first month for a recheck and readjusted him again telling me to continue riding and strengthening.
He is fine at a walk, and can trot as long as it is a straight way. I cannot ride him in the arena or lunge him because he is very lame around the turns, with the shoulder on the inside of the curve. He would rather canter than trot. He's not as bad going the other way. We have been 4 months into this injury (Sept. 9, 2011)
We have a pond to ride around so for 3 months about 2 or 3 days / week I've been lightly riding and strengthening him...sure to stop when he shows signs of discomfort.
I havent seen any improvement, so since the weather has gotten cold and it's difficult to ride him outside (the ground is soft and slippery around the pond) I've decided for the past month to rest him and just hand walk and stretch him for awhile. I rode him down the road for a short distance last week (after 2 weeks rest and hand walk) and he seemed to be feeling really good. I let him trot for a short way just to see if there was any improvement. He did not seem to be nearly as "gimpy" .... he's been back on rest since.