Since you have a couple of issues going on and the components that would cause your problems are located on the bottom layer of the board I think it would be safe to say that some of the solder pads that secure the top and bottom layer of the logic board have become cracked or torn off. There is not much you can do if you haven’t got the experience or the equipment to separate the two boards and inspect the solder pads.
The cost to repair your phone will depend on the damaged to the solder pads.