I’m really wondering how you can tell if you have breast cancer or not?

I do a self exam every month and I feel like even if I feel up my breast I still wouldn’t be able to tell... the tissue is not that smooth so it’s not like it would significantly stick out to me.

I feel like I might have found something but then again it could just be part of the tissue. Going in to the doctors next week for check

Advice on if there is any other way to tell at Home? Or if there is anything you do that you find helpful?