Thank you for the query.
nodes in most common cases gets enlarged due to infection in the regional area. However it should be always ruled out with metastases of a cancer. Inflammation related lymph nodes are movable, sometimes painful, and get enlarged in a few days. Cancer related lymph nodes are usually hard, not movable, and do not cause pain.
The best way to have it checked is to perform ultrasound
and make a biopsy
of such lymph node. You should also have your breasts checked and have ultrasound of it.
Hope this will help.