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1.The history and symptoms suggest the possible cause could be
breast abscess which is of infective aetiology - painful sore breast.
2.In case of hard and not very painful the causes all be
breast cyst, ductal ectasia, mass lesions.
3.In any case you need to get an
ultrasound examination done which will evaluate the nature of the lump its source and extensions.
4.in case of mass lesion an FNAC - fine needle aspiration cytology need to be done to know the nature of the cells involved. Depending on the age
mammogram correlation needed for the tiny / micro calcifications.
5.Suggest to get appointment with your GP, get examined and needful investigations and treatment accordingly. Good luck.
Hope i have answered your query,
any thing to ask do not hesitate to ask.
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