i think i've only developed the waddle in the last couple of weeks. i did get lower back (and some upper back) soreness by around the 20 weeks and i was in pain every time i got up from sitting or lying down. i went to see an osteopath & i haven't had any upper back soreness since & my lower back has been much better. my lower back has just been getting sore in the last couple of days & it's been a month + one week since my last visit.