Sakit pinggang masa pregnant memang common sangat, usually sebab baby growing, posture berubah, dan ligaments jadi softer, a few of my mum friends said they kena teruk around your trimester too. Try to maintain posture yang baik, avoid heavy lifting, pakai maternity support belt kalau boleh, dan gentle stretching atau prenatal yoga memang tolong banyak. Tapi sebab ni pregnancy-related pain, better check with your gynae to make sure everything okay dan dia boleh suggest physiotherapy if needed.