Aiyooo, at 33 weeks senggugut-senggugut macam tu memang common lah, especially kat pinggang area, boleh jadi Braxton Hicks atau just the weight of baby pressing down, a few of my mum friends rasa the same thing during third trimester. But nak make sure it's nothing concerning, better check with your doc or midwife to confirm, esp if it keeps happening or gets worse, jangan risk je kan, they can rule out anything else and give you peace of mind. In the meantime, try warm compress and make sure you rest enough!