The album tells the story of a rock star called “Pink.” Pink is a fictional character, but he has a lot in common with Roger Waters.
Pink is a guy who’s totally alone and isolated from the rest of the world.
He couldn’t relate to other kids when he was in school, he can’t relate to women (he’s pushed away his wife, who’s now sleeping with another man), and he can’t relate to his fans (who he’s now regarding as stupid sheep).
He feels as if there’s a wall that prevents him from connecting with other people.
Most of the album is set in his hotel room, where he’s getting high and having flashbacks of events from his life. He’s looking at his cold mother, his sadistic teachers, his father’s death in World War 2, and trying to understand how all of those things contributed to making him the lonely misanthrope he is now.
Everything that ever went wrong in his life is one piece of the puzzle, one part of the wall that cuts him off from the rest of humanity.
There was no one thing that isolated him. There were MANY things, and each is a part of his problem, a symbolic brick in the wall.