ok, this is purely anecdotal, but this has given me fits for about a year and I thought it might help someone else.
Last year I felt a really bad twinge in my lower back while riding to work. It got steadily worse, then throw in some severe-make-you-cry-like-a-baby sciatica leg pain. My doctor was sure I had a herniated disk, so off to the MRI machine I went. Nope, nothing there, seems I have the spine of a 30 year old (I'm pushing 50) So, off for a CAT scan, where they found an inflamed SI joint. The neurosurgeon put me on Celebrex, and mercifully, the pain was under control.
But it's been bugging me about a year now. All my bikes have Brooks Saddles, and it occurs to me that while I love them, the lack of padding does not dampen road vibration, so I swallowed my saddle snobbery and bought a specialized sport touring saddle, a Dolce. Not a lot of padding, but some, and put it on my LHT, which I'm using for commuting right now. The difference has been amazing. I am off the Celebrex, and I'm riding pain free. I'm making the switch on my other bikes as well.
Now it's entirely possible that I have just healed. The doctor said this would take 6-9 months, but I could have trouble with it for the rest of my life. The thing is, when I ride on a brooks, there's some irritation afterwards, and not with the Specialized. BTW, I did try a brooks with springs, didn't help. I did a search for this topic, Didn't find anything saddle related, so I thought I'd just pass this on. Still getting used to the padding. Thanks for reading.