Chosen Solution

My screen has a crack from the middle left to the middle right and has now started to lift very badly. My other problem is that now my iPhone keeps on constantly resetting itself.

Do you have the 2 screws in the bottom? If it does you probably need a screen replacement. The constant resetting seems to be a problem most likely related to something on the screen shorting out on the motherboard. You could very easily replace the screen yourself for much cheaper then apple or a repair shop could for you. Hope this helps and good luck fixing!