Hello and welcome to Healthcare Magic. Thanks for your query.
From the description of your symptoms, it appears that you may be having a swollen lymph
node below the jaw. Lymph nodes can get enlarged whenever there is an infection or inflammation in the surrounding area which it drains.
Neck nodes are common in throat infections and oral problems. Since you are having only a single node, you don't have to worry much, but in case you develop fever
or sore throat
or increase in size of the swelling or any other complications, you have to see a doctor for a physical examination.
Wish you all the best.
Dr. Sheeba Stephen
Emergency Medicine Specialist