Without commenting on the rest of your comment, I would like to clarify a point:

Let me try to explain this better, then. Imagine we take a person who needs surgery but was never told by their doctor what part of their body the surgery will be on. We perform the surgery without any anaesthetic and with the patient blindfolded. In this case, the pain is giving new information ("AAAIE! MY RIGHT LEG!") but we still don't approve.

The first little twinge (also, mechanical sensation that is not pain) in any given spot tells them what's going on and is useful. The rest of it that sums up to "AAAIE!" is useless-and-therefore-bad.

Also, it's common for someone to not want to know what's going on; they would prefer, not just the absence of pain, but any sensation, any information from the body part(s) involved; this is reasonable and, I would argue, a separate module from the badness of (some) pain.