Occasionally lymph nodes can become infected with a bacterial or other type of infection. It is possible that you have an indolent infection in the lymph node such as with an atypical mycobacteria or other bacteria.
This location is pretty rare for a bacterial infection to be but it may be worth a trial of antibiotics to see if it clears up.
I would recommend seeing your doctor for a follow up and further discussing your symptoms.
Advice and opinions given are based on the information provided and must not be considered an official medical recommendation. The limitations of the internet prevent an appropriate evaluation. Always consult your doctor if there is concern.