Hey, good dream! And yes, you were very much lucid.
When it hurt when my mom twisted my arm did I move in a bad position in bed and thats what caused it?
Well, if you just randomly felt a pain in your arm it's possible that it came from outside though not particularly likely as far as I know. But since the pain happened in response to something in your dream I would say that it was just in dream pain. There is nothing out of place with that. It simply means that you had a vivid enough lucid to feel pain. I view it as a good thing. Nice one!

As far as forgetting stuff, that is just dream recall. It will get better with time.