My microphone stopped working

Hey guys,

so a few days ago my microphone stopped working. I own a black 5s 32GB and whenever somebody calls me they cannot hear me. But If i put my phone on speaker they can hear me (since the iphone has multiple microphones). So i suppose its the one right next to the headphones-plug-in. Anyways, I have watched many videos on how to fix an iphone yourself (e.g. screen crack) and i "kinda" know my way around this field. And since I thought it must be a hardware error i ordered a complete new dock connector (this product in case somebody wonders:http://www.amazon.com/s/ref=nb_sb_ss_i_5_21?url=search-alias%3Daps&field-keyword s=dock+connector+iphone+5s&sprefix=dock+…

But somehow everything is working on the phone except my microphone....again.

Now im clueless and I'm here. Has anybody ever heard of this error? Is there something wrong with the software or is it maybe the logic board? Should I restore my phone and put a (already saved) backup on there?

Thanks