Wa'alaikumasalam! Sayang, any belly pain in pregnancy kena check dengan doctor, even if it's not frequent okay? Better safe than sorry, terutama first baby. Boleh jadi normal ligament stretching (round ligament pain, semua pregnant mums experience), tapi some of us kena make sure tak ada apa-apa lain. Please book an appointment with your gynae or go to clinic soon and mention this to them, they can examine you properly and put your mind at ease. Don't worry yourself lah, but do get it checked!