Any definition of harmful that doesn't include say, electro-shock torture and water-boarding is a really really bad definition.
Hint: Pain really is intrinsically harmful.
Those come under 'injuring in such a way as to cause the person to develop PTSD', and no, it's not.
Tyler Cowen argues in a TED talk (~15 min) that stories pervade our mental lives. He thinks they are a major source of cognitive biases and, on the margin, we should be more suspicious of them - especially simple stories. Here's an interesting quote about the meta-level: