Iphone5c mic won't work with anything but calls and voice recorder including Siri.

sstarted as soon as I updated to os8.1.4 but I have been playing with the phone and noticed something that points to hardware after I restored phone and had no change. if I touch my screen by the camera it nakes the screen go black only when attempting to use Siri but if I push the home button it comes back on not locked. If I I continue to squeeze the camera area with light pressure and activate Siri the microphone works it also works in Voice texts and other apps. But this has to be done while trying to use voice commands even if I switch to speaker while in call.