How do people get passions?

I honestly don't get it.

It's so bizzare to me when people have topics or passions to talk about. Like talking about favorite bands, cars, tools, programming, anything really.

I mean, there are things I am interested in. I like history, middle ages and the likes, and I wanted to learn more about it but everytime I read a historical book or watch a documentary it just feels like a chore.

I want to write, and now and then an idea pops in my head, some longer than others, but again, when I get to it I need to fight for enough concentration to push through.

I really don't feel like I would need to exhaust myself to have some hobbies. And it's not a good exhaustion, like after a nice workout. It's a sluggish mental backlash that punishes me for trying to do anything interesting.