Some years back, when my two teenage sons were about 2 and 3 years old, and I was still married to their father, we lived in the countryside and had no running water or electricity. I was highly stressed out. I developed an itchy and burning area in the middle of my upper back, sort of centred between the lower end of the shoulder blades, directly on my spine. The area was very slightly raised, and warm to the touch. It was roughly round (but flat) in shape, with little bumps like tiny itchy bites, and about a quarter the size of my palm.
I wondered if I'd been bitten by a spider or something, but when the burning seemed to get worse, I went to my doctor - on about the 4th day. He said it was shingles and if I recall correctly gave me some lotion to put on it,and tablets to take. I cannot remember exactly, but I think it was over a week before it cleared up completely.
The feeling is a bit like really really bad sunburn - a burning, inflamed feeling.
Last year I developed something similar all along the inside of my one arm, from my armpit to the inside of my elbow. It felt just like the last time I had had shingles, but this time I couldn't see any raised area or rash. Because I couldn't see anything, and because I kept thinking the "sunburnt" feeling would go, I waited nearly 2 weeks before I went to the doctor. It was apparently a sort of "invisible shingles" - the doctor suspected post-herpetic neuralgia - a nerve damage disease, somewhat related to shingles. He warned that I may have to take tablets for the rest of my life to keep it under control, but luckily after about another 10 days, taking some tablets he prescribed me, it was gone.
I believe it is difficult or even impossible to get shingles if one has not had chickenpox, and that it is also difficult or even impossible to get post-herpetic neuralgia if one has not had shingles.