I've had my phone for about six months and recently it felt like the battery got pretty hot. Since then, instead of needing to charge the battery once every two or three days, I now need to charge it three times per day. I do not have anything running either. Blue tooth, wifi, mobile data is all turned off.

Is this something that I can fix?

you could try updating to the latest firmware+factory reset. Bu it sounds more like o hardware issue of battery or board. If nothing helps I suggest to contact your seller for help. If you like to repair by your own you could search if you find that parts on platforms like aliexpress.