Karen -- I had a fibroadenoma before my first pregnancy.  Lump grew gradually
with each menstrual cycle till visible to naked eye about 1-1/2 inch long and
1 iinch wide.  Mobile.  Tender.  Was sent to breast surgeon who palpated with
appropriate vigor and was confident enough in his diagnosis to take no
further steps.  It disappeared, along with other much smaller cystic lumps,
after breastfeeding my son.  This does not sound like your problem -- more
likely an abcess?

Joanna Koch, IBCLC