Hi, Cancer of breast has high chance of spreading to the ipsilateral axilla (armpit). The lymph node if swollen most probably will be positive for malignancy. Because there is the staging system based on clinical fining only.Still there are some clinical features suggestive of metastatic lymph nodes like hard, non tender swelling. Anyway , nothing to be worry about there are excellent treatment for breast cancer available. Follow your doctors advise. Take care.