Hai! Sakit tulang rusuk masa pregnant memang boleh jadi normal, especially time 31 weeks macam you sebab baby dah besar dan pushing against your ribs, tapi since ini first baby you better check with your doctor just to make sure everything's okay, especially kalau sakit tu intense or persistent. A few of my mum friends went through the same thing dan they said it gets better dekat 3rd trimester, though some rasa sampai labour jugak. Meantime try sleeping with extra pillows to support, jangan terlalu charge yourself, dan if it gets worse atau you're worried, jangan hesitate to call your gynae, better safe than sorry! Take care, dear!