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Okay I've been breastfeeding for almost 3months and of course had pain in the beginning. I went to work the other day and let myself get overly full, I pumped and since then my left nipple hurts. It's a burning pain and it has been over 5 days, I've used lansinoh, no bra, let it get air. It just continues to burn. Could it be a plugged duct? An infection? Help it hurts. Thanks.