Momsh, yan talaga ang ligament pain na common sa third trimester kaya normal pa yan! Pero since sobrang sakit na talaga and affecting your movement, mas safe kung i-check mo with your OB para masiguro walang iba, especially at 31 weeks na, they can give you specific stretches o suggest a maternity belt na sobrang tumutulong sa marami sa amin dito. One of my mum friends swore na the belt made such a difference with her round ligament pain, kaya seryoso I'd recommend getting checked and asking about support options!