Chris, you may have issues with your headphone jack. It will switch the speaker etc. off when a set of headphones is plugged in. So if the jack is stuck, your phone will turn off the external sound. Try to insert and remove a headphone jack a few time in rapid succession. You can also try to clean it with some isopropyl alcohol, a few puffs of compressed air, as well as a small non-conductive cleaning rod i.e. toothpick. If that does not help you may have to replace the headphone jack. Follow [guide|4337|this guide] for that. The part is available [product|IF182-016|right here] as well as many other places. Hope this helps, good luck.