What Causes Hard Lump Above The Breast?

I have had a hard 1in lump above my breast for over 5 years now. Should I be concerned that it has not gone away. Went to get it checked out 5yrs ago and the doctor told me it was normal for someone with large breasts to form these, then laughed at me for getting a mammogram for it. I should have gotten a second opinion for it then, but was humiliated and didn t.