Ay anak, importante talaga na ikonsulta mo agad ang doctor mo about sa heaviness at pain na yan, lalo na sa left side, hindi dapat i-ignore yan kahit gaano kaliit ang concern! 16 weeks pa lang, kaya maraming posible reasons, pero kailangan talagang i-check ng professional para sure ka. A few of us moms felt weird sensations around that time too, pero bawat pregnancy talaga ay different, kaya wag mag-worry kung ano exactly, just go to your OB na and let her examine you properly, okay? She'll know exactly what's normal and what needs attention. Sana mabilis malinaw ang feeling mo, and I'm rooting for your pregnancy!