Purgatory is a place (or state) where we are exposed for who we are. As our pitiful attempts to live righteously are exposed to the bliding Light of Christ, as our selfishness, our bad habits, our chronic sinfulness is peeled away to reveal the true adopted Son of God which we were always destined to be, there is a mental anguish.
Purgatory is also a place of great joy. While the process of being scrubbed might hurt, there is a joy in knowing that we are only steps away from eternal bliss.
SD
Becky