Hi fybroman (clever name, BTW!), I get odd sensations here and there. I often can't sleep on my left side because of a weird feeling there---not even sure how to put it in words. It's almost as if it's impossible for any muscles there to relax, even a little. Just impossible to get comfortable.
I think fibro can disguise itself in all kinds of ways. Currently, I'm in the midst of a flare that is literally all over my body. It feels like a sinus infection that has literally taken over my body---how strange is that??! But I've noticed it "hits" harder in various areas. Such is this monster called fibro!
Have you seen a neurologist or had nerve testing, an MRI, or anything like that? That's one thing that really eased my mind. Though I've had fibro for many years, I generally get the same sort of pain, sensations (or loss of), but it can vary enough at times to make me second-guess myself. If it's too worrisome, I do go and have it checked out.
As far as affecting both sides of the body, my current bout is doing that, but generally I have more issues on my right side, for some reason. I do have something else going on besides fibro, though, according to my neurologist; something neurological.
Always a good idea to sit down with a good doctor, talk about
anything that concerns you, and move on to testing if it's needed and/or eases your mind.
Wish you the best! Hope to see you on the forum again, and hope you get some good answers.