I'm a bit devious, but here's what I'd do in your position, Lymer- use at your own caution - LOL! I understand though, because I have to be careful of repercussions from docs around here as well. That's why I'm not welcome in most doc's offices any more! Oops!
I would go to a couple of Fibro forum and see what words they are using to describe their pain, and be sure that the words you choose to use come from those experiencing the same type and as close to the same severity as you experience, or as close as possible. Then be sure to use those words to describe your pain. Write it down!!
Sometimes we have to do what we have to in order to get the help we need -so don't let that stop you!! I didn't have a toddler to chase around when I was at my worst, but I couldn't even take care of myself at that point either. You need help and you deserve the help, so let them believe you are there because of Fibro pain!!
Just my 2ยข worth!!