Chronic Pain patients tend to minimize their pain. pain *i don't really care about seeming normal. i just don't want my family to know how bad it is, because there is nothing they can do. no reason to make them feel bad too.
Validation is a calming comfort to those dealing with chronic pain. Even though it doesn't take away the pain, it does let the person know that you empathize with them. Just saying the words, "I believe you" can do so much for a person.