Lower back pain

hi mummies, currently im 17wks. did anyone of you experienced sharp lower back pain when sitting for a short while (15-30mins) or for too long? currently working in the office which obviously require long sitting hours. i did get up and do some stretching whenever i feel extremely back pain but it came back every time i sat down. how do we overcome this since we cant use salonpas patches/koyok. #firsttimemom