Help, when I call, I can only be heard on speaker!
Tell me if this sounds familier: unless you place the phone on speaker when you are on a call the other party cannot hear you. Well, this normally means that your headphone jack is not functioning correctly. This could mean that it has been water damaged, it broke somehow or that something is stuck in it not allowing it get out of the headphone mode. First, get a flashlight and look into the headphone jack. Second, make sure the phone is turned off and if possible the battery is removed. Clean it out with a toothpick and compressed air. Check to see if you have a water damage indicator and see if it is red. If it is, then you will need to replace the headphone jack. Third, get a q-tip and and go up and down the headphone jack to dislodge anything that could be keeping the contacts locked up. If this doesn't work, take the phone to a trusted tech.