Does your horse's hoof look like one of these? All these horses are in pain, although you might not notice it. The only way to solve this is taking off the shoes and hire a good barefoot trimmer and start rehabilitation. You can not cure this overnight. The hoofs are the basis of the horse, so any hoof problem is a fundamental problem. And since a hoof problem stands not alone, a healthy diet, enough movement, and the right terrain are as equally important as a good trim.
Note: All pictures were taken by me, before my first trim.