Thanks for posting,
If swollen and sore then it is probably mastitis
(is the inflammation of breast tissue. S. aureus
is the most common etiological organism responsible, but S. epidermidis and streptococci are occasionally). You will require antibiotics in order to eradicate the infection. If my assumptions are correct, then your baby would not be able to feed from the affected breast or if the baby continuous you might instead infect her. I suggest you get some medical help
first before you may continue breast feeding.
Hope this helps and wish you the best.