Yes, sometimes pulling a horse's shoes causes them to be instantly 'tender' & others it takes a while to come on. When horse's feet are very compromised, shoes can indeed alleviate the pain of the problems, but they can't fix it, so removing the palliative allows the symptoms to resurface. Perhaps he's so much worse this time because the problem has progressed a lot more since he was last out of shoes? It sounds like it's time to start addressing the problem.
Hmmmm ok, it's a friends horse, that needs to be spelled out because of heaves, however because of the icy conditions outside he cannot be out safely with those darned shoes on.....I might suggest another alternative....thanks for the info