My Apple headphones won't work on my iPhone and only on my iPhone?

I have an iPhone and my apple headphones were working fine for one second but when I unplugged them and plugged them back in it doesn't work and the sound comes out of the speaker. I thought it was the headphones but they work on my computer and anything else. Other head phones work on my iphone, I tried 3 other headphones and they were all fine. It's just my apple head phones that don't work. Does anyone know how to fix this?

Can I upgrade my iPhone at an AT&T store instead of online?

So I'm eligible for an upgrade from my 4s to a 5s but I was wondering if I was able to do this in a store, meaning just walking in and asking for a new iphone. All I read online was logging into your att account somehow doing it that way. Well I'm not the holder of the account so I don't really want to just go in and do that. However, I have all the necessary information such as account holder name, SSN, and billing address. Can I just walk into an AT&T store and request an upgrade there? If thats possible, does anyone know how its done?

Does iphone 5s/c need syncing to computer?

Well the reason i've said 5s/c is because they both are shipped with ios7. Problem is, my computer is broken, won't even come on. And i've ordered a 5s and with the other iphones you had to plug it into a computer for it to come on? Do you still need to?

Iphone problem! Unknown error 21?

My iphone 4 just randomly turned itself of and i tried to restore it but it said 'unknown error 21' can someone please tell me how to fix it?

How to get a picture off your camera onto instagram?

For my birthday which is very soon in about a week infact, i'm getting a canon camera as one of my gifts.
Now I follow many people on instagram and they have pictures that they have taken with their camera on their instagram, even if its just landscapes, their pets, a picture of them or a picture of them in the mirror with the camera. And they write in the description taken with my canon camera so on…
And i'm not going to lie, I'm quite a big fan of instagram as many are and when I have my camera I'm going to want take pictures off their and put them onto instagram, but I have never got how you do that.
Do you have to put them into your photo library first? Or straight into instagram, even so I don't know how to do that.
I have an Iphone 4 by the way incase that helps because it might be different for other phones.

How to get my iphone back to normal?

I bought a second hand I phone 3 off a friend who had previously jail broken it. When I got it I restored it to factory settings and now it won't turn on. It just comes up with the apple logo. How so I get it back to normal?