Could it be something along the lines of...
You currently know that there are 2 states, awake & asleep. You've woken up from asleep & remember doing it. You've never woken up from awake that you know of.
From the way I'm interpreting that, it still doesn't address how pain is experienced only when you're awake and never when you're dreaming.
What I have of it so far:
I wake up from dreaming -- pain does not exist.
I have never woke up from awake -- I can't be certain if pain exists.
Unless, forgive my misinterpretation if it's erroneous, you are getting at the point that the pain we perceive to experience in the reality of being awake doesn't exist, like how it doesn't exist when we are dreaming. In other words, you're implying that there is another state of awakening above what we believe to be awake where the realm of pain actually exists?
Am I getting that right?
Edit: If that were the case, then how is it that we are able to distinguish between pain from no pain (awake vs dreaming)? Wouldn't we still believe that pain exists as an actual thing in being awake? Put another way, how do we know that in dreams, we feel no pain, but in being awake, we do feel pain?