Oo, normal talaga ang back pain sa 6 months preggy dahil sa weight ng baby at nababago ang posture mo, pero kung sobrang sakit at di talaga nawala kahit ano pa gawin mo, better check with your OB para ma-assess kung may underlying issue or kailangan ka lang ng proper support like maternity pillow or prenatal massage. A few of us mums had the same issue at nalaki lang siya when we didn't address it early, so don't hesitate na mag-consult agad, walang masama sa pag-check, at baka may simple solutions lang na hindi mo alam para mawala ang saket mo!