Sakit belakang dan tengkuk masa pregnant memang biasa, tp kalo sampai terasa nak muntah macam tu, better cepat check dengan doctor or midwife kamu, ada kemungkinan postur, tension, atau even something yang perlu attention. A few of my mum friends had similar pain towards the end and most improved with prenatal massage or just adjusting how they sit (boleh guna pillow support), but at 31 weeks dengan pain level tu, jangan ambik risiko okay.