Hi - what determines whether you get a core needle or fine needle biopsy?

I went in for a routine mamm & they asked me to come back in 6 mos which i just did last week. They think they see an enlaged (by a millimeter) lymph gland in my left breast almost attached to my chest wall. Now they want me to have a needle core biopsy. Why not just a fine needle aspiration (FNA)? Why do they need to punch a bigger hole in me? I'm pissed they didn't even offer the FNA as an option - only the coring. Plus, as I explained to the 60 yr old white, male (of course) doctor, I've had a mild case of herpes since 1981 which your system is constantly fighting at a low level. When I get close to an outbreak I can literally feel the lymph nodes in my neck swell. "Really??" was his response. Where the hell did he get *his* medical degree, was all I could think... I worry I am getting an unneccesary hole punched in me...thoughts? (I know - better safe than sorry). m.