phone heating and becoming really laggy

my phone randomly stopped working one random day where on the top left of back sides is heating up to 42C if left on for to long my battery drains like normal its just that it heats up after 10 minutes and becomes really unresponsive and there is a lot of delay the only way to stop it from heating is by powering it off and for it to stop lagging I just restart the device finish any quick work I have and turn it off again
something to mention is that I've dropped the phone a lot and the only visible damages is the front screen protector being cracked and the backplate being cracked and it can be removed