The walking motion of a horse mimics the walking motion of a human (when riding). That's why it's used for therapeutic riding for those with developmental problems. It can help build muscles and coordination in those who can't actually walk.
Granted this isn't you, but it might provide relief because you aren't getting the actual impact of walking while still working those muscles.
If your horse says no, you either asked the wrong question or asked the question wrong
And God took a handful of southerly wind, blew His breath over it and created the horse