Hello, this is Dr. David. I have read your question and I'm ready to help.
a sour throat is a sign of acid reflux from the stomach coming up the esophagus to the throat.
a sour throat can cause sore throat and difficulty to swallow.
usually thyroid conditions don't cause throat symptoms unless your thyroid gland is super large and causing a gloiter mass pressure on your throat. you would be able to see your thyroid gland if this was the case.
if you have acid reflux, you will need stomach acid blocking agents like prilosec or prevacid
and acid neutralizers like malox or mylanta to help decrease stomach acid
you might have to change your diet to avoid certain foods which worsen stomach acid like tomato sauce, alcohol, sodas, fried foods, oily foods, spicy foods.
37.4C is 99.3F which is a low grade temp and can occur from even a viral
throat infection or ovulation or other causes.
do you have a history of acid reflux or sour throat?