radiologist was not very reassuring...

Hi,
Welcome to ehealthforum,
The armpit swelling could be the swelling in extension of breast tissue (axillary tail of breast) that gets active in few women. Other possibilities for the breast discharge includes PCOS, hyperprolactinemia, hormonal changes. It is difficult to comment on the underlying cause for the breast lump that you describe without further evaluation. Causes could be injury to breast tissue, fibroadenoma, cyst, fibrocystic changes, mastitis, cancer, etc. Do not delay your visit to your doctor/gynecologist or taking second opinion from another gynecologist. Look out for development of other symptoms like fever, radiating pain or worsening of pain, changes in skin covering breasts, changes in nipple, etc. If there has been history of breast cancer in your family, getting a screening mammogram along with tumor marker test done will be helpful to predict your chances of developing breast cancer. Biopsy done from the lump can help to prove cancerous/benign nature of the lump. Further treatment options would be discussed with your treating doctor/gynecologist based on examination findings and investigation results. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.