Phone constantly freezing when touch is used and restarts at random
I have just replaced the rear camera on my phone.
Having turned it on, the phone is now almost unusable as any kind of touch movement I do is laggy, freezes and sometimes does not respond at all. Along with that, while the phone is being used, it restarts at random. Prior to doing so the screen's colors will distort or gray out.
The phone also no longer updates the battery % (for example will show 100% until it manually restarts) , takes longer than usual to read SIM card, the home button seems to fail sometimes.
This is quite serious yet I don't see what could have gone terribly wrong when replacing the camera for this to happen, not to mention I've teared the phone apart various times with no problem. I only forgot to unplug the battery before the screen and one time unplugged the battery while the phone was on (the power button stopped working and there I was stupid for not remembering that can also be done with assistive touch).
Any leads on the cause for this?
Edit: Having once restarted the phone myself, it then did so on its own 4 times within about 6 minutes of usage and then no longer restarted. Could mean there's a pattern to the restarts.
Edit 2: Resetting phone settings solved the freezing problem. For a while the restarting went volatile, happening every 3 minutes but now seems to have stopped. Shutting the phone off and on manually seems to trigger a restarting spree. I don't really need to turn off the phone, so I'll just stick with this for now. I think there's some hardware problem as I've tried pretty much anything that you can do to stop these kinds of restarts and it was to no avail.