Be it removal of shoes, conformational corrections, or the reduction of excessively long heels to allow contracted hooves to open--all of these result in a change in the stresses (pressures and tensions) within the hoof, associated ligaments and tendons, and/or joints. It stands to reason that the effected tissues will require some time to become accustomed to these.
Usually, every tissue of the body, every cell, is replaced after a certain amount of time, depending in part on the rate of metabolism. However, when there is a change in the tissue, or a repair is necessary, sometimes the usual rate of metabolism is not sufficient. Increased circulation and increased blood supply become necessary--in other words, inflammation. Within the hoof, increased blood supply is painful because there is no room for the excess blood.
THIS IS WHY, IN MANY CASES, WITH CHANGES IN THE SHAPE OF THE HOOF, COMES INFLAMMATION OF THE CORIUM.
This is generally impossible to avoid, since the reshaping of the hoof toward its normal, physiologically sound form cannot take place without inflammation--which disappears as tissues and stresses once again harmonize.
The better the circulation and blood supply, the faster the change in the tissues, and the quicker the inflammation will be over. This is why exercise (using common sense) is necessary for quick healing. Immobilization of the hoof means less blood supply and circulation, and thereby slower healing.