While You’re the only one able to judge your personal experience and I can only go by what you have written, I have close Friends and relatives who had similar experiences. Runny nose in particular was not seen as a Covid Symptom in adults by health authorities at the time. Chest Pain is a common symptom of anxiety. All my Friends who had similar symptoms and got antibody tests prior to vaccination had no Covid antibodies. Let me suggest an alternative explanation that might or might not also apply in your case. Constant stress and anxiety about catching a horrific disease or loosing family members lowered the immune response as it is a well known effect of stress. Being fully vaccinated not only lifted that anxiety but also gave the immune system a boost. Thus no more infections with beta-coronaviruses and other viruses that caused the runny nose.