Catherine Wheel, Mancudera, Exposure
Catherine Wheel: How much pain can your muse withstand?
Given that he survived being scorched by Amaterasu and later on the extraction of a bijuu (and the recovery thereafter) without special family abilities and/or outside assistance (Uzumaki stamina, Gaara being revived by Chiyo, etc.), which has never been done before, it’s safe to say that he can withstand quite a lot of pain.
Mancudera: What is the most physical pain your muse has felt?
By far, the most pain he has ever felt was when Gyuuki was torn out of him during the last war.
On top of already being absolutely exhausted (breaking through the numerous barriers that had restricted himself and Naruto, facing off against the reanimated Jinchuuriki, morphing into Gyuuki’s full-sized form and maintaining it for an extended period of time, forming and firing off many bijuu bombs in rapid succession. and so on), to have the Hachibi ripped out of him felt as though his very soul was torn apart.
(The soul might not be a physical thing, but that’s the only way he’s ever been able to come close to describing the pain.)
Muscles torn, most of him severely bruised, and all around beaten to the very brink of death, even he is surprised that he even managed to survive the ordeal, and he credits it entirely not to his own efforts, but to Gyuuki’s, because he strongly believes that had the Hachibi not sacrificed one of its tails to encase him in, the severe pain would’ve killed him before anything else had the chance to.
Exposure: Would your muse rather freeze to death, or burn?
Between surges of electricity constantly flowing through his body and being set aflame by Sasuke, he’s had more than his fair share of burning alive.
He figures that freezing to death would be much easier to deal with, given that one would eventually lose consciousness anyway, and everything would go numb before that.