Why is my phone overheating?

@delanopamina heat=short circuit. since your "battery drains faster than normally" I would start by replacing the battery first, then re-evaluate. Since iFixit does not have a guide for this, use something like this video to replace the battery.

While you work on your battery, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this. Repair is War on Entropy!