**Core Concept**
The patient's symptoms are consistent with mastitis, an inflammatory breast condition that can occur in lactating women. Mastitis is often caused by a bacterial infection, but it can also be triggered by ductal ectasia or poor breast-feeding technique.

**Why the Correct Answer is Right**
The correct answer is to continue breast-feeding from both breasts. This is because mastitis is not a contraindication to breast-feeding, and in fact, breast-feeding can help to clear the infection. The continued flow of milk through the affected duct can help to flush out the bacteria and promote healing. Additionally, breast-feeding can help to reduce the risk of abscess formation and promote the immune system's response to the infection.

The patient's symptoms, including pain, swelling, redness, and warmth, are all consistent with mastitis. However, the absence of fluctuance or induration, and the lack of pus, make an abscess less likely. The key to managing mastitis is to continue breast-feeding and to treat the infection with antibiotics.

**Why Each Wrong Option is Incorrect**
**Option B:** Breast-feeding from the unaffected breast only would not address the underlying infection and could potentially lead to mastitis in the other breast.

**Option C:** Starting antibiotics and breast-feeding only when antibiotics are discontinued is not necessary, as breast-feeding can actually help to clear the infection.

**Option D:** Pumping and discarding breastmilk until the infection is over would not be effective in clearing the infection, as mastitis is often caused by bacteria that are present in the milk.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that mastitis is not a contraindication to breast-feeding, and in fact, breast-feeding can help to clear the infection. The continued flow of milk through the affected duct can help to flush out the bacteria and promote healing.

**✓ Correct Answer: A. Continue breast feeding from both the breasts**