Hi,
Welcome to ehealthforum,
The symptoms that you describe could suggest pregnancy chances (possible due to contraceptive failure). The breast lump could be due to breast tissue response to hormonal changes, lipoma, abscess, fibroadenoma etc. You should consider getting the lump examined by your doctor/gynecologist and go ahead with further investigations (mammogram, ultrasound scan etc) to look for the underlying cause. Get started on treatment as indicated by examination findings and investigation results. If you suspect chances of pregnancy, consider visiting your doctor/gynecologist at the earliest for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). 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.