I don't know what has happened really, when I woke up it was just powered down and then when I was opening it, it just got stuck on the Apple logo and i've been trying to restart it by letting battery die and plug it into the charger to see if it would help, but no, nothing, it just doesn't start-up and gets stuck on the Apple logo. How should I fix this?
Plug it into a computer with iTunes and put it into recovery mode. You do that by holding down the power and home button, waiting for it to turn off, then let go of the power button but keep holding down the home button. If you do it correctly, you will see a red iTunes logo. You can then try to update the device to get it working, but you may have to restore it. I've seen this happen when the phone runs out of storage space or when the iOS software is too out of date.
It did not help. I haven't dropped or wet or done anything it, still keeps jamming in the Apple logo.
Realistically, from what I recall, those two are essentially the same with the main/only difference is that with DFU you provide the installer while with recovery mode it automatically downloads the latest installer.
Here's a guide showing how to put your iphone into DFU mode: https://www.theiphonewiki.com/wiki/DFU_Mode
I'm having the same problem, but after restart my iPhone, It's solved! As an iPhone 7 user, I just press and hold the volume down button with still holding the On/Off button. Keep holding both buttons for 10 seconds and its restart your device.