It is does heat

@heenapatel38578 the rebooting and the heating up could be caused by a dead short on the motherboard somewhere. You will have to partially disassemble your phone. Then disconnect all peripherals like the fingerprint sensor, charging sub-board flex, cameras and antennas from the mainboard. Leave only the screen and battery connected. Try to power it on.

If the phone boots up and doesn’t get too hot, then the short is in one of the peripherals you disconnected. Reconnect them one by one to see which one causes the heat and bootlooping (common would be a bad charging board or a bad camera). It is also possible that his is caused by a faulty battery. You definitely would want to change that as well.

If the motherboard alone still bootloops and overheats then the short is on the motherboard itself. To fix that you would need to have the schematics, tools and experience to do a boardlevel repair. Let us know what you find out.

To work on your phone and since iFixit does not yet have a specific guide for this, use something like this video

While you work on your phone, 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 who has the same issues with their device. 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!