microphone not working

Try to record a voice memo. If the option is grayed out it's Audio IC failure ("loop disease"). Quite a common hardware bug on 7/7+. Make an encrypted iTunes backup and bring it to a trusted repair shop or Apple Store.

Hi fizafrompakistan,

here’s a link to an apple support page that may help you: https://support.apple.com/en-us/HT203792

hope it helps!

Charles