Oo, round ligament pain yan most likely! Alam ko yan kasi parang ganyan din ako nung 16-17 weeks, sobrang nakakatakot pero normal lang talaga siya sa pregnancy, yung ligaments are stretching as baby grows. A few of us in the mommy group had it, lalo na pag umakyat ng stairs or bigla kang bumangon, grabe ang sakit but it passes naman, walang problema sa baby. Still best to mention it sa OB mo just to be sure everything's okay, especially kung tumatagal or nagiging malakas, pero I'm pretty sure it's just your body adjusting to the pregnancy!