So you're unable to hear anything through your headphones when they are plugged into your iPhone. That sucks, lets do some troubleshooting.
Is there anything stuck in the jack?
If there is it's probably lint and you could carefully remove it using a small set of tweezers. Keep in mind that most repair shops would be happy to do this for free and they will probably take care of it for free. We end up doing this and resolving charging problems upwards of four or five times a day!
Does the Loudspeaker Work?
If the loudspeaker is not working this typically indicates that the headphone jack is registering something inserted. This could be anything from defective soldering on the jack to damage to one of the conductors. In most cases replacing the jack entirely is the best course of action in this situation.
Try a DFU Restore
Last step before replacing the charging port would be to perform a full backup of your iPhone using the following instructions  provided by Apple and then following these instructions  to perform a DFU Restore of your phone and ensure that there is known good new firmware installed. The firmware facilitates communication between software and hardware and if it's not working properly in some cases it can cause strange symptoms like this.
If none of that helped then the Charging Port/Headphone Jack Assembly likely needs to be replaced. Feel free to get in touch with us using the contact information at the bottom of the page if you're in Oregon. If you are outside of Oregon we'd still be happy to perform any necessary repairs for you, but you'd need to fill out the mail-in repair form at the following link ::