Sakit pinggang macam sengugut memang common masa pregnant, terutama bila dah masuk trimester ketiga, beban perut pulling on your lower back lah. Tapi sebab ni involve pain yang sharp or cramp-like, better check with your doctor or midwife just to be safe, especially at 25-26 weeks ni. A few of my mum friends had similar aches and it turned out fine, tapi yang lain kena rest and physio, so really depends lah. Sementara tu try lie on your side with a pillow between your knees, and avoid standing terlalu lama kalau boleh.