No matter how hard I think, I cannot seem to manifest any true pain in my mind. I doubt a pig could either.
We do not know that simply being severed from your body is simply experiencing no sensory input of any kind, and actually have a lot of reasons to expect that would not be the subjective experience for very long.
(Bizarrely, the dream pain has nothing to do with anything in real life that should have been pain. Apparently my subconscious is fine with dismemberment or stabbing or whatever, but what really bothers it is removing my orthodontic spacer from the roof of my mouth, which apparently it feels is me trying to remove the roof of my mouth. Subconsciouses are weird.)
[1]: https://www.britannica.com/science/phantom-limb-syndrome