I once found a lump in my breast, about 3 years after I'd stopped nursing my youngest. My doc felt it as well, and got me in for a mammogram very quickly. I don't know what it was, but that machine squeezed the heck out of my breast & the lump disappeared. Perhaps it was dried milk in a nodule or something??

Hope that you get in for your mammogram soon & find reassurance as well. Take care!