Dear worried86, The most common symptom of breast cancer is a painless lump. There could be a number of causes for this pain and discomfort, the first step in finding out what might be causing this is having yourself evaluated by a health care professional. They would be able to ask questions regarding the history of the problem and do a physical examination.
i was wondering if you ever found out what was cause the lump to appear under your left armpit. I am having very similar symptoms and under the same arm. if you know the cause of this, please contact me. thanx