The common cause of swelling in armpit is enlarged lymph nodes. Cysts
and infections of the armpits can also cause enlarged lymph nodes
in armpit. Other causes of armpit lump are cat scratch disease, lipomas, infectious mononucleosis, lymphomas and breast cancer. Vertigo can be caused by inner ear problems, neck injury; migraine etc.You should see a primary care physician. After a general examination your doctor may refer you to the concerned specialist based on the clinical findings.