It's from chicken pox. If you have had chicken pox you can get shingles.
Also when I first got it the doc told me to stay away from pregnant women.
I thought the shingles virus was related to the herpes virus which causes cold sores, or so I was told. I guess I was misinformed, but I did get a very bad cold sore during the time my grandmother was with us. That one was the worst, but the recurring ones (every few years) are not nearly as bad and clear up quickly.
May the Lord keep us all free of diseases and afflictions. They are not fun, to say the least.