I've Had The Tender Back The Last Three Weeks. The

I've had the tender back the last three weeks. The skin is tinder very very light swelling in areas upper back only in the skin tissue I have had absolutely no injuries stresses or anything muscular in the way of bodily injury. . No scratch no sores no lesions most of the skin looks perfectly normal except for slight red tinges in small areas.. In the last four months I have had shingles vaccination. I have had the chickenpox. Or smallpox whichever thiat is the problem.
Could this be small flareup of shingles? Or are there other more serious problems but I should be looking to?