What is an enlarged golf ball sized lump under my arm pit?

An enlarged Golf ball-sized lump under your armpit could be a lymph node that has become swollen due to infection, inflammation, or other medical conditions. It may also be a cyst or a lipoma, which are generally benign growths. However, if the lump is persistent, painful, or accompanied by other symptoms, it’s important to consult a healthcare professional for a proper diagnosis and treatment.