Wa'alaikumassalam sis! Sakit bawah perut sebelah kanan masa pregnant memang biasa, especially masa trimester ketiga, boleh jadi ligament pain atau baby dah besar sikit dan pushing on one side, tapi sebab ni first pregnancy you, better check with your doctor just to be sure everything OK, especially kalau sakit tu terasa kuat atau ada bleeding. A few of my mum friends had the same thing around 29 weeks and it settled down, tapi doktor tetap want to rule out anything else. Hang in there, you're almost there!