Matt Asked: Lucid Dreaming- Painful Trance Before Sleep?

Last night I was attempting lucid dreaming- as I would reach the trance-like state before knocking out completely, I would try to set myself up for the dream to a certain degree of success (I couldn't tell if my body was actually moving or not until I snapped out of it completely.)Accordingly, I kept having nightmarish things happening to me as I was doing so (can't say exactly what they were other than nightmarish), which my conscious mind was trying to block out while simultaneously setting up the dream.So I kept yanking myself out of this state and trying again.Over and over I would partially achieve the set up, and I eventually started feeling an extremely intense pain shooting up and down my left side in the skin, particularly on the hip, like a constant electric shock as this happened.I can't say how many times I tried, but eventually I'd had enough and decided to succumb to the sleep state.Does anyone know why the pain might have occurred?I've never had any of this happen to me, and this subject isn't widely publicized on the internet, so if you know anything about it your insight would be greatly appreciated, thanks.