I can't write pain.
I think it's because I don't really feel pain.
Let me explain. I am a person who hasn't ever experienced real pain. Muscle soreness? Yes. Toothache? Yes. Bee stings? Yes. Fingernail crushed in a closing car door? Yes.
Broken bones? No.
Serious lacerations? No.
Ruptured organs? No.
I've never been in a serious car accident. I've never even experienced whiplash from getting rear-ended. I have lived a remarkably pain-free life.
So when I try to write about pain, I can't. I'm currently trying to edit/clean up my first novel. There are scenes of vicious physical aggression in this embryonic novel (they'd be called "fight scenes", but this is Literature, and Literature doesn't have "fight scenes". It has "scenes of vicious physical aggression".) The most significant problem I'm confronting in this Augean stable of fiction is making the scenes of vicious physical aggression...believable.
I think the problem is that I can't communicate the weight of the fights. I can't say how it would feel to be punched in the jaw by a strong man, because I have only been punched in the face once, and that was not by a strong man. I haven't really had my head smacked in punching fashion--by a door, say. I can't feel my characters' pain, because I have no point of reference. So when I write down my characters' pain, my readers (probably; there haven't been any yet) don't feel the characters' pain. And the scenes of vicious physical aggression lack weight. The reader might even say, subconsciously, "so what?"
And that's never a question an author wants to hear.
To lend weight to this conjecture, there is the matter of loneliness. I don't think I'm being melodramatic when I say that I know what being alone is. I'm a naturally solitary person; I cultivate a few close friendships, and that's it. And if those few close friends are unavailable, well then, I am alone. I'm fine with being alone; I have come to know being alone.
I write loneliness well, I think. One of my earliest short stories is microfiction about an old man walking up a hill, pursuing memories. There are all sorts of tangled strands of interrelated theme that squirrel about in the story, but running beneath all of them is a heavy line of loneliness. I still love reading that story. I go back to it, and I say "I wish all of my stories were like this."
My point is this: I know loneliness, and I write it well. I don't know physical pain, and I write it poorly. Coincidence?
Long live loneliness.