I got them in the middle of my back when I was pregnant at age 29. Ugh, horrible pain. Although it cleared up, I still have nerve damage there 25 yrs later. Can't stand anything going across the middle of my back. ("convenient" for us gals, huh? )
My mom had them when she was going through chemo, couldn't stand anything on her skin. I felt soooo bad for her. She said it hurt more than anything she'd ever gone through.
Unfortunately, it is cause by a virus and once it's in your system, it's there. They can be dormant for a long time, but you can develope outbreaks again. I believe it's related to chicken pox (but don't quote me on that one)