Alam ko yan, sobrang uncomfortable talaga ang ganitong pain sa pregnancy, a few of us moms experienced similar rib pain around that stage, usually kasi lumalaki ang uterus at nagsisikip ng space. Siguro naman dapat i-check mo with your OB just to be sure it's normal round ligament pain or pregnancy-related, kasi better safe na may peace of mind ka; pero in the meantime, try changing positions frequently, avoid staying in one seat too long, at some of my mum friends swear by proper pregnancy pillows to support the side better when sitting. Intindi ko talaga na mahirap, pero definitely worth mentioning sa next check-up mo!