Sakit kepala memang common during pregnancy, but at 24 weeks you should definitely check with your doctor to make sure everything is okay, a few of us pregnant mums experience it, but it's better to rule out anything serious like high blood pressure or dehydration. My gynae always says if it's persistent or really bad, don't wait, just go in. Make sure you're drinking enough water, getting rest, and eating properly, sometimes it's just fatigue and dehydration playing tricks!