Girls, hello! 37 weeks pregnant, the baby is very heavy, my back hurts…

Girls, hello! 37 weeks pregnant, the baby is very heavy, my back hurts all the time but I try to walk a lot, there's been a lot of discharge without smell or color, but the doctor says it's normal, does this happen to everyone? And still, this uncertainty scares me, how will I know that contractions have started? Is it painful to give birth ???