Hello and welcome to HCM,
Painless lump under the armpit is most commonly caused by
lymph node enlargement.
Development of new lymph node near the bigger swelling can be due to enlargement of another lymph node.
It is suggested to consult your doctor for clinical assessment.
Lymph node enlargement is most commonly caused by infections, inflammation and metastatic tumors.
Is there any associated lump in the chest?
Whatever may the case a clinical assessment is required for further management.
An aspiration cytology of the swelling is required to know the origin and nature of the swelling.
Aspiration cytology is an office procedure wherein a needle is inserted into the swelling, cells are aspirated and spread on a glass slide.
The cells are stained with appropriate stain and studied microscopically.
Thanks and take care
Dr Shailja P Wahal