Welcome to health care magic.
1.A lump behind the left nipple area with
redness, possible cause could be cyclical changes, autoimmune as you have some issues with it, and infective aetiology.
2.In this case you need to get an
ultrasound examination of the breast - that will help to know where the lump is from ( muscle, fat, duct, skin ), what is the nature of the lump ( solid, cystic, mixed) and then finally where all it is extending to.
3.That will help to get a conclusion, at least you have mentioned what description given in the report would have been helpful.
4.Depending on findings - if mass FNAC- fine needle aspiration cytology, If cystic structure / infective cause - a small
incision and drainage will help.
5.Suggest to see the surgeon as told and get needful treatment - good luck.
Hope i have answered your query.
Any thing to ask do not hesitate. Thank you.