Solid Mass Hematoma
That might help with your Google searching.
As for you being punished, get that thought out of your head. You've done nothing wrong. These things just happen. That's not the best answer, but that's the answer we've got.
As for the surgery, will it hurt? Yes, it will. It's surgery. The doctors will either knock you out or give you local anaesthetic to just the breast tissue. They'll remove the mass and stitch you back up. You're going to have a scar. Depending on how you take care of it, it may fade away a bit.
It's a good thing that the doctors are taking the mass out. Even if it's not cancerous, it should be removed. If it is cancerous, you're very young. You'll do just fine. You'll get the treatment you need. The best thing for you right now (and the people around you) is a positive attitude. Do some research and inform yourself. Ask your doctors questions. Ask as many as you want. There are no dumb questions. You have the right to take up as much time as you need. Do not let your doctor rush you with your appointments or questions. Do what you need to do to make yourself comfortable.
My Mom had breast cancer. And she's had many non-cancerous masses removed. She's just fine. When she had cancer, she had the most positive attitude. For her it was "Okay, I have cancer. Let's get rid of it." And she did just that. Had chemo, lost her hair, had radiation. And she recovered.
So, inform yourself, ask questions, and remain positive!