Hi, MysteryLyme, and welcome! Maybe you are grinding or clenching your teeth at night and causing pain in that area. I've never heard of that specifically with fibro but I guess it could happen.
Be sure to check out Fibro 101...the second thread on the forum. There are link to good info about fibro and you will learn a lot there. There are links to Symptoms that you might want to read and also A Thorough Explanation of Fibromyalgia. This might help you see if you possible could have fibro too.
I hope other chime in and have better answers than I do. Fibro, as well as Lyme, have some pretty strange symptoms. Meanwhile, don't hesitate to ask questions and we will try to answer them. I'm looking forward to getting to know you better and also hearing more from you soon.
Sherrine