Mommy, please go to your doctor or OB right away, especially since may nana na involved, kailangan niya tignan in person para sure. That's not something to monitor lang at home, okay? It could be mastitis or something else, pero hindi ako makakaalam without proper check-up. One of my mum friends had something similar and kailangan ng antibiotics, so please don't wait pa. While you're waiting for your appointment, rest muna and observe kung bumubuo pa ng init or kung lumalaki pa. Your health is super important para sa baby mo rin. Sending you healing thoughts, sis!