C.S.
J.,
I haven't had this happen to me personaly (I'm 29 and havn't had one yet) however, thi has happend to my Mom and to one of my Aunts. It's fairly common, but it must be addressed. They need to make SURE it's not something that needs treatment.
Everyone has 500-600 lymph nodes in their bodies, your lymphatic system is basically a filtration system. Lymph nodes act as filters, with an internal honeycomb of connective tissue filled with stuff that will collect and destroy bacteria and viruses. When the body is fighting an infection, lymphocytes (the stuff that collects and destroys) multiply rapidly and produce a characteristic swelling of the lymph nodes.
Once they swell, if they are in the breast they can look like a tumor (growth). Once they've finnished destroying whatever bad thing is in there they shrink right back down to their normal unnoticable size.
So really, in this case, you don't have anything to worry about. You can enjoy your relief!! Hope that helped.
(((hugs))) <--- cuz I know you need em!
C.