That's because most Dr.s don't explain much! Recently I saw a Physiatrist that told me chronic pain and the fatigue that comes with it causes brain fog.

I was told it was a result of a past trauma, could be physical or/and mental. An accident or abuse of some sort.

I am positive fibro is caused by stress. A lot of emotional things went on in my life. One was my son started having seizures at 18 which I almost lost him that was one cause. The other was an abusive marriage which is now OK but the disease can never be reversed once the nerve damage is done. They say it's over active nerves which is true. I hope it helped a bit.

I keep scouring the internet for information, and I have found no clear theory by anyone. It remains a mystery.

It is because they do not know the cause of fibro.