All of the above.
It’s a non-issue.
Two identical twins are distinct from the moment they form experiences.
No different in any variation of clones thus presented.
I can think of a few complicated scenarios though.
Identical triplet boys raised to see only one of the others as “me” and their own body as “one of my two identical brothers”.
If they are always within visual contact of each other, I can imagine that when their assigned “me” gets hurt, they feel the pain themselves from afar. This is an ability that comes with being human, at least most of the time. (feeling pain you imagine another is having).
But, would they then NOT feel their own body’s pain when hurt?
I imagine pre-verbally, they’d experience their own body’s pain, building necessary connections for that.
But if the switching is introduced within the first 9 months and continually reinforced without error, I think they could learn to ignore their own body’s pain so long as it was acknowledged properly by the other triplet that was trained to feel it.
The problem would only happen I think if they ever lost sight of one another for any length of time. Without anyone to reflect their pain back to them, they’d have to deal with it themselves, which would probably be a mind-shattering experience.