I may please be allowed to take the honor to welcome you to HCM. I just went through your explanation and came to an conclusion -
You might be suffering from "parotitis"......... followed from an URTI. Hypothyroidism
, in particular has NO role to play with it as you had sore throat
I would suggest you to apply cold compress over your parotids. You can add one NSAID
group of drugs for pain and inflammation relief with vitamin "c". I personally in my clinical practice, adds clindamycin
in such situation. I cant prescribe drugs here as not allowed by HCM.
You being a senior person, i request you take care of yourself and get consultation of your local doctor before taking any drugs.
Finally, i wish you an early recovery and a very healthy life.