Hello. I would suggest downloading a new camera app, but you did mention this problem only started a few days ago...you can go to or contact your local phone store and they will help you. I hope this helps.
Hello. It might not be the actual headphones. More than likely there is a setting on your phone that can direct the sound to your headphones. It happens a lot to me, but I change the settings to "headphones" from "internal speaker" and it works every time. I hope this helps.
Sometimes there's a little chip inside of the phone that controls the storage, and everything else. You can look for a close-up diagram of your phone to see what I'm talking about. Also, the quality of the phone depends on where you get it, how new it was, and how much you paid for it. Yes, I understand phones are expensive, but make sure you buy one that isn't ridiculously cheap. Like the saying, "You get what you pay for." I hope this helps.