Hi mama! At 36 weeks, some belly and back pain is pretty normal kasi heavy na talaga ang baby and your body is stretching, a few of us pregnant moms experienced the same thing towards the end. But since you're already close to your due date, mas better na i-mention mo ito sa OB mo next visit just to make sure everything's okay, especially if it's getting worse or may other symptoms like spotting or contractions. Take care of yourself, and message us anytime!