Overheats

So, my phone got overheated out of no where, this happened 23 of december. I’ve tried everything since then to get it back up and running, tried letting it cool down over a day, turning on flightmood while charging, turned off all background programs etcetc. But it gets overheated of just charging and also charges like 3% per hour. Has aynone had the same problem and what did you do? Cuz I guess my only option left is to change the battery.