The suffering of Finn isn't literal in the show, its the hijacking of his character by the writers for whatever they need him for
Example, Vault of Bones. We've seen Finn go exploring dungeons plenty of times. He's not careful, he doesn't nitpick details, and generally rushes in with abandon. But because the writers need to make le funny video game jokes and make Flame Princess look good, Finn becomes this boring NPC mouthpiece for the episode.
This becomes more prominent as the show goes on, until the only consistent thing about him is about how annoyed his supposed friends are with him.