Software does play a big part in mastering these days and there's a wide range of different options available.

You do need to know what you're doing and you need to be able to listen and hear (which is harder than it sounds to many).

the listening part i feel confident in. i can hear things that no one else i am ever physically around can here in music. that doesn't make me an expert or know it all, i would be brand new to mastering. buuut i do know what i want to hear, and it would be just playing with the software and reading up on it to learn how to achieve the end goal.