Thanks Joyfull, I was a bit confused for a minute there, too.
flyxfish, thanks for all the extra info. It does help to know more about your girl.
The fact that there is no smell, scabbing, dampness or discharge in the area means it's probably not a fungal or bacterial infection. The spots or pimples are likely to be new feathers growing back, under the skin.
To me it sounds like your chicken may be going broody. As Bantam Novice mentioned, chickens often pluck out their breast feathers when they go broody. This allows them to keep their eggs warmer. It is a bit puzzling if she has never laid an egg though.
Has she shown any other changes to her behaviousr - like sitting longer on the nest and not wanting to come out?
Is there any chance of you posting a photo for us to see? It's very hard to guess what might be wrong without inspecting her. This all might be something perfectly normal, or it might be a problem... it's just so hard to tell!
P.S. Glad to hear that your own health is good after your hospital visit.