Panganganak.

I think that's natural. I've experienced that. And based on what I've researched kaya sumasakit puson natin and private area is bec yung uterus natin nag aadjust ang size kasi nag go-grow pa si baby. But just to make sure, you should go to your Oby-gyne and ask about it. Mas ma e-explain nila at para ma check na rin ang development ni baby.