Talk to Cancer Specialist / Oncologist on Breast Lump

I have this lump on upper left side of my right breast. Its been there for approximately 3 years. I have lactated 4 of my kids perfectly fine. The lump is pea sized and is still the same size. It is not painful. But it feels as if ifs attached to my skin. Like i can feel and hold it from my skin. I consulted a dr once and she said its ok i shouldnt worry. As i breast feed so there is less possibility its cancer