Touchscreen of my iphone 5S ONLY WORKS while charging?

I'm having trouble with my iphone 5S right now, the touchscreen only works when I plug in my phone but, when i don't charge it, the touchscreen doesn't work very well, also when i use it like a lot, the phone starts working but when i don't use it that much, the phone just got freezed
it's getting really annoying guys, hope you can help me out with this, have a nice rest of the day

Front camera on iPhone 5c has stopped working?

The front camera on my phone has stopped working.

Sometimes it's just a black screen, other times it's a frozen blurred image.
Bottom line is, I can't take pictures using the front camera.

How can I fix this?

IMessage Suddenly changed to a different number?

Out of the blue my imessages started sending from a phone number I have never seen before. Texts still send from my number, but when I go into IMessage settings, send and receive, my number isn't even an option. I can receive texts and send them, but can only receive imessages on the random number.
We switched carriers, but this was 3 days ago, and I have not had this problem until now. I tried to reset factory setting but that did not work.
I have the IPhone 6, running iOS 8

How much storage will be taken from me if I updated to ios8?

So a new update came saying that improvements are made for those iPhone 4s who updated to ios8. I'm just wondering if the storage taken will be bigger than the update on ios7.

My phone was 16gb but when I updated to ios7 it became 13.3.

I have now around 3.5gb -4gb will that be enough?