Good question. I've not seen it addressed but I have noticed over the years that trauma, physical or mental, often triggers the symptoms.

I have had Fibro for over 10 years and just this year (2019), I was diagnosed with Shingles. I suffered for about 4 weeks. It left me with intense marks on my skin.
My mother also had Fibro and I recall her having Shingles at least twice.

I think that shingles and fibro have stress in common. Certain things seem to cause an exacerbation of fibro, and other things will cause an outbreak of shingles. At least for me this is so.

I have had viral meningitis twice, so I am sure that aggravated the fibro and made it worse.