They are both right, but combine them for a bigger picture. He did have the idea of the wall after feeling bad about spitting at a fan (the fan may have deserved it, thier 'fans' had a habit of lighting fireworks and being disrespectful to the band and music). To express this feeling he used the story of pink, who was forced to confront his own demons that had turned him into this totalitarian rock star. These demons stretched back to the childhood explored in most of the wall, especially his relationship with his mother, teacher and wife/girlfriend figure. In this song, he is inside his head confronting these demons and his own insanity/confusion. The mother, I beleive, is also a figure he has issues with, as explored in the rest of the the album and especially in the film with the flower symbolism, representing his issues with women, which arises from his relationship with his mother. She doesn't protect him, she stifles him.The film is essential veiwing for understanding the album, and a layered exploration in its own right.