I make or receive a call no one can hear me unless there on speaker and mute button is on.
Always make sure that the mic has not been muted when you make or take any phone calls. Also, if the caller on the other end of the line can hear you when you are using a headset with a built-in mic, then there might be something wrong with the mic of the phone itself. In which case it be a good idea to have the phone checked at a nearby service center.