My Macbook Pro is getting hot when I'm not using it, why?

This has been happening for the past week or so. My 2014 Macbook Pro will, for no reason at all, get extremely hot even when I haven't used it for the day. It feels like I've been using it for hours on end, when there will be days that I didn't even touch it, and yet it still is extremely warm. In fact, the only time it cools down is when I'm using it, but it still feels somewhat warm.

I have no idea why it does this. Does anyone know what's going on or how I can fix it?