Need to re-paint small strip of my car?

I got a 2010 Chevy Cobalt for my birthday and it's in great condition, aside from a few dings that can be easily filled in with paint pens meant for scratches.

The only real concerning part is the small strip on the driver's side doors. It's only about an inch or so tall and stretches almost the entire length of the doors (I don't know if these have an actual name, I'm fairly clueless about cars).

Anyways, it's oxidized and I want to paint it, either the same red as my car or black. I don't care is it's a little off in color, but is this something I should really take to a professional?

It's just this one spot and i feel like it'd be easy to fix, and I don't want to break the bank or end up painting my entire door since it's raised about a half inch forward and isn't the door itself.

So would this be easy to do with some simple car paint and a brush/ sprayer with the rest of my door covered up? Or would i have to take it to someone