Constipation in pregnancy is really common, especially in the second and third trimester, but it can definitely start earlier too. The hormones relax your bowel muscles and the iron supplements don't help either if you're on them. Every 3-5 days with pain in between isn't ideal and worth flagging to your PD or gynaecologist, just to make sure everything's fine and they can suggest what's safe to take for relief. In the meantime, lots of fluids, high-fibre foods and maybe some gentle movement might help ease things a bit.