I remember not too far back I had a natural lucid dream. There’s just one issue: I had this weird, throbbing soreness all over my body. It’d gradually fade in and out, just like my vision, though that part usually happens when I’m sitting around, thinking. Any thoughts? That and sleep paralysis are the things keeping me from wanting to do this stuff.

When you stop and think for a moment, maybe you can feel back part of your real body, who can be aching from the uncomfortable position. Do you wake up feeling a similar pain?
Also, sleep paralysis is something that happens all the time when we’re not noticing, and it is a very good way to enter a LD from wake. This topic can give you a hand on the subject.

Just to give a little bit of personal experience to tosxy’s point, I’ve had a couple of issues of falling back to sleep in a very unusual position. The pain from my leg transferred into my dreams. Were you aware of any back problems with your mattress?

Now, if it wasn’t your RL body, you have the advantage of the fact that it all in your head. You just need to tell yourself you’re not really in pain, or that the pain will leave, etc. A slightly easier way of doing it for a beginner might be the dream pill. Just pull a pill out of your pocket, and tell yourself it is an instant acting pain reliever.

As for SP, if it really bothers you, you might want to try some techniques that don’t rely on it. Some examples include MILD, VILD, RCILD and CALD.