In my years at the clinic I have seen many cases much like the one you describe so much so that "Have you ever injured your breast?" is now a permanent part of our history taking. Seat belt and steering wheel injuries are most common. Blows to the chest can occur in sports or simple rough housing. Usually the mother can identify an incident involving her breast that hurt "for days". A horse kicked one mom when she was a teenager. When her milk came in you could see the outline of the horseshoe imbedded in her breast. In these cases it can be assumed that the ducts were crushed, hence the trapped milk resulting in tenderness, redness and swelling. If the ducts were crushed, it can be assumed there is no outlet for the milk, which will back up behind the injury. It seems that the milk will remain sterile if there is no inlet for common bacteria. Most of these mother's do not have mastitis. They remain afebrile. What we do is selectively "dry-up" that portion of the breast. Cabbage compresses, ice and no extra stimulation to that area. Our mom with the horseshoe took several weeks before she was pain free. But she continued to breastfeed. She never developed mastitis. I have serious concerns about the multiple courses of antibiotics.: What good are they doing? Are they really needed? Marie Davis