Sakit area kelengkang masa pregnant ni memang sangat common, especially dah masuk 6 bulan, someone in my mum group mentioned it could be something called SPD (Symphysis Pubis Dysfunction), where the hormones like relaxin cause the pelvic joints to loosen up more than usual, and naik tangga every day memang will make it worse. Ramai yang rasa lega sikit with a pregnancy support belt to help take some of the pressure off the pelvis, and trying to avoid big movements like wide leg steps. That said, since sakit kelengkang boleh juga come from other causes like urinary infections or pelvic inflammation, it's really worth mentioning this to your doctor or O&G specialist soon so they can check properly and advise the best way to manage it for you, sayang.