I feel a lump under my arm pit but I think its a lymph node, is this something to worry about?

Depends. How long has it been there? A few days, weeks or months? Is it painful. Did you have a recent injury, cut or infection further down that arm in the past few days. Watch it closely. If the lymph node is noticeable after 3-4 wks, seek immediate attention with your doctor. The arm and 3/4ths of the breast drawn to the lymphatics in the armpit. If it goes away, it was a reactive change.