Why can't I hear the recipient of my call except on loudspeaker?

When on a call I can only hear the other person when i press the speaker icon on the screen to activate the loudspeaker. I have noticed that when I plug the charger into my phone it doesn't give me an audio notification now and I think this is relatedasthey have happened at the same time. Have turned phone off and I and checked all the settings 'phone', 'general' and 'nori cation' settings. Have also checked the volume when on a call to no avail. Hopefully someone can help or I will have to take it in for repairs.