Aih sayang, back pain boleh jadi normal masa pregnant tapi if it's sharp or senggugut-senggugut like that especially when you're lying down, better check with your doctor or midwife cepat-cepat la Siapa tau ada apa-apa that needs attention, better safe than sorry kan. A few of my mum friends had similar pain around that time and turned out dia kena round ligament pain or muscle strain je, but some needed a bit of physio atau adjustment, so best you get it checked properly so you can manage it properly and rest comfortably lah. Jangan tunggu, go see your doc soon okay!