Aww sayang, at 24 weeks memang banyak perubahan kat perut kan, ada kemungkinan ia round ligament pain (ligament yang support uterus stretch), or baby position yang bikin one side rasa tight je. Lepas tu posture boleh jadi culprit jugak, kalau kita duduk lama or tidur position yang sama. A few of my mum friends experience this juga, and one of them felt better after try sleeping with pillow between knees and side-sleeping more (left side usually comfier for baby circulation jugak). Tapi since this is pregnancy discomfort and 24 weeks is quite specific, worth checking with your doctor just to make sure everything okay je, they can feel your belly and confirm if it's normal stretching or something else. Hope you feel better soon!