Hi, I just did a factory reset a some days ago, everything was good for just a few days, then it happened. I was attending around in device memory.
The long story tells you short. Reformatted SD, it works fine now. Thank you.
If it isn't working I would suggest trying to factory reset the phone. That's when you hold the power button and home button at the same time. That should hopefully work. Sometimes your whole phones just needs to restart itself. Another thing that you could do is to completely delete everything from your phone. I have done that a couple times and it works for me. You can find how to do that in your settings. Make sure you back everything up on your laptop though because you might lose it all. Then if nothing works I would say that you should call Apple. They are really helpful people and they will take the time to help you. They are all really great at their job. They will be able to help you so that you're phone will work again.