Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand..
As per your complain swollen and painful structure under the jaw can be due to two reasons:
1. It can be due to a swollen lymph
node secondary to infection..
2. It can also be due to obstruction in the duct of the submandibular salivary gland
or due to infection in the gland..
You should get it confirmed by consulting an Oral Physician and get evaluated and a thorough clinical evaluation can help in diagnosis..
You can also be advised to get investigations done like x ray
of the gland and treatment can be planned accordingly..
As of now you can do alternate warm and cool compresses over the swelling and take Ibuprofen
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.