It's not uncommon to experience sharp pains and a bump on your stomach during the 15th week of pregnancy, as this may be related to your body adjusting to the changes. However, if the pain is severe, persistent, or accompanied by other concerning symptoms like bleeding or unusual discharge, it’s important to consult a healthcare professional. Given that you're in Singapore, you can contact your obstetrician or visit a local clinic for further evaluation to ensure both your and your baby's health.