This is a great video showing how important is the evaluation and treatment of the neck of the horse.
In this video Dr Rullan talks about the neck , how it can be overlooked during a lameness examination and how it can be injected in order to alleviate its pain.
4 Main Signs of Neck Pain
Stiff neck and unwillingness to flex the neck
Stiff back
Multiple limb lameness
Tripping
If your horse has any or multiple of these signs, then most likely your horse has hock pain.