microphone doesn't work only for phonecall

I have issue with the microphone of my Iphone...

It doesn't work but only for phonecall!

Sometimes people can hear me for a minute but then noises are coming but most of the time people just can't hear me but I can hear them.

But the thing is, it's working if I'm making a video or a voice memo or even when I'm putting the call in loud speaker or with hands-free!

The phone has never been in contact with any liquids.

What do I need to change??

I also have the power button who's not working but I already found what i needed to know to repair it on your site.

thank you and sorry for my bad english.

I also have the power button