what's the least painful way to remove mold?

Depends where it is. On hard non-porous stuff (tiles, sealed grout, glass, bath) a diluted bleach solution or a shop mold spray works fast - spray, leave 10 minutes, scrub, rinse, and open a window. On painted walls I'd use white vinegar neat in a spray bottle instead, leave an hour then wipe. Bleach just whitens the stain on porous surfaces without killing what's in it. Wear gloves and a mask whatever you use. And if it keeps coming back in the same spot, the damp is the real problem - an extractor fan that isn't pulling, or a cold wall.