I do warm compress when my milk is clogged up. Some suggest to put cabbage near your breasts, and I've tried it once few days after I gave birth, and it helped relieved the pain.
Expule milk. I did it, it was a bit of pain at first but you'll feel light right after. Tip: breast pumps are not good.
A self breast massage will do to unclogg.
Warm compress and then breastfeed more.