I don't know for certain if I had long covid but I experienced weird symptoms in my body beginning in January when there where >30,000 new cases per day in my country.

I was fatigued, had unexplainable chest pains some of the time, had problems concentrating, headaches, always a runny nose. I never did a antibody test because I self-isolated for most of the time and never met people without a mask, so I initially thought I was just developing an allergy. Multiple doctors tried to find out what was wrong but all tests where pointing to me being very healthy.

Then I got my second mRNA shot in July and all those symptoms went away, like magic. Very weird for me and maybe I had long covid and what you described happened.