Aw, mama, iyong back at leg pain ay medyo common sa pregnancy kasi lumalaki na ang belly at nagbabago ang posture mo, pero at 17 weeks pa lang, mas maganda siguro kung i-check mo na with your OB para sure hindi ito something else, better safe than sorry, diba? A few of my mum friends nag-experience din ng ganitong ngawit pero they were further along na, kaya definitely worth mentioning sa next check-up mo para ma-guide ka properly on stretches or support you might need. Wishing you a smooth pregnancy!