I copied this from a site. It worked for my sister.
"If it is too painful to nurse, express milk by hand while in a warm shower or tub or hang your breast over the sink and run water over it, as you gently massage toward the nipple.
Do not wear tight fitting clothes or nipple shields across the breast.
Warm, moist heat applied with a compress or hot water bottle will help unplug the ducts and ease swelling. Herbs that work well in a breast compress are anti-inflammatory and reduce swelling (comfrey, chamomile, calendula, lavender), increase lymph circulation and drainage (cleavers, burdock root, yarrow), and draw out infection (slippery elm, marshmallow root). Mullein leaf relieves pain. Pour boiling water over the herbs and steep 10-15 minutes. When cool enough to touch, apply herbs as a poultice, or dip a cotton cloth in the warm infusion, wring it out and wrap around the breast and under the armpit. Keep the poultice on until it cools. Reapply throughout the day. If infection is present, a clean poultice or cloth should be used every time.
Try a grated potato or cabbage leaves on an engorged breast to draw out inflammation. It can be mixed with hot water or applied cold, whichever feels better.
A home remedy that has been used successfully to unplug ducts is to drink a small amount of undiluted apple cider vinegar."