Wa'alaikum assalam! Sakit dekat pusat tu mmg biasa masa mengandung, especially tengah-tengah pregnancy, ligament stretching and all that, tapi since ni first pregnancy and you're considering caesar, better check with your doctor to make sure everything's okay la. A few of my mum friends had the same worry, and it turned out normal je, but everyone's different so don't self-diagnose! Your OB will give you peace of mind and tahu exactly what's happening with your body.