Ay alam ko yan, first time mommy jitters talaga! Yung sakit na yan sa perineum area (the area between your butt and, um, you know) ay common talaga around 16 weeks, sometimes it's just ligament stretching, nerve pressure from baby growing, or your pelvic bones adjusting na, lalo na kung walang bleeding at intermittent lang. The back and side pain din ay normal part ng pregnancy, pero since this is your first time at gusto mo ma-ease out of your mind, best talaga na i-mention mo ito sa OB mo sa next checkup para she can confirm everything's okay and maybe give you specific stretches or positions na makakatulong.