I am an occasional lurker - used to post on another board with some of the oldtimers here, who helped me out when I was going through a very similar time to you. I had no family history, but lots of fertility treatment and miscarriages...which my surgeon explained had probably added to the fibrocystic changes. I had lumpy areas in tne breast (nowadays in both) and was diagnosed with fibrocystic changes after a core biopsy. I still have mammos and u/s every year, and exams - it would be hard to biopsy every lumpy bit these days, but they all feel the same: sort of rubbery, ridgy, and lumpy as opposed to distinct lumps. When I doubt something I feel, I run back to my surgeon - just in case.
I was told it was quite common for women to develop these changes in their forties (I was 40 when I first had them) as hormones fluctuate more, but mine were not cyclical and never left - in fact, they have increased. Not unusual, in midlife, apparently.
My big miracle..I had a daughter at 43, and after that the pains and lumpiness calmed down considerably for a couple of years: again, my surgeon had told me to expect that. Unfortunately, its temporary! Though they are likely to calm down again in menopause.
Anyway..I do'nt usually chip in here, except to check on old friends, but could relate so much to your situation. I hope this helps even a little, and am glad you found the same amazing support from these women as I did five years ago.
xxxClaire ps if you are not satisfied with a FNA, you could ask for a core biopsy? If you trust your surgeon, discuss it with him - he may have good reason not to need one, but I would want to know what those reasons were and be satisfied too!