Welcome to health care magic.
1.If you had included your age that would have been more helpful. However if reproductive age group - the possible cases could be ductal dilatation, breast inflammatory changes feels like lumps.
2.Any where after 40 years with or with out family history can suggest possibilities of malignancy.
3.Othere possible causes of lumpy feeling cyclical breast pain
/ heavy ness can be seen in hormonal
imbalance - for which hormonal treatment is given.
4.The next step you need to get an ultrasound
scan, the ultrasound scan will detect the lump, its nature, its source and extensions. In case of mass lesion an FNAC - fine needle aspiration cytology will assess the nature of the cells involved.
5.In case you are above 40 years a mammogram
correlation for the micro calcifications should be done.
Hope i have answered your query,
any thing to ask do not hesitate to ask.