Yes, it is.
Once you have any herpes virus, it's with you for life. So yes, you definitely have VZV in your nervous system.
As for me, I first came down with shingles at age 37, during a relapse from one of my earlier ME episodes. The next time was at age 46, at the same time I had my final relapse, which has lasted until now (16 years). This happened exactly one day after I had an old herpes zoster lesion removed because it had turned carcinogenic. A couple of years later, I had my final case of shingles.
Both of the last two cases were much milder than the first one.
My chickenpox at age 5 was one of the worst cases my doctor had seen. I was literally covered head to toe with the chickenpox lesions, even my eyelids. The lesions were side by side - there was virtually no uninfected skin. I really did look like a plucked chicken! It was very painful, and I ran a high fever. I still remember it clearly today. All those bottles of Calamine lotion...