Maybe she has, maybe she hasn't. We'll never know unless she says.
As someone has already pointed out, her weight has steadily gone down during the course of her life in the public eye. She was pretty big to begin with, smaller by the time 21 came around, a lot more trim when 25 was released (but had definitely put on again by the end of the tour) and then we've barely seen her since so what we see now is perfectly achievable without weight loss surgery, although I suspect she'll have had work done to tidy up any loose skin (but she may not have had any if she's working out as much as she claims, the weight loss has probably been gradual plus she's young although she did have a section so maybe she wanted that sorted) But I do think she's had a boob job. She's certainly not adverse to surgery - look how much her face has changed and that ain't all down to weight loss!
I went from a size 24 (I was probably pushing a size 26 if I'm honest - I just refused to buy that size) to a size 10/12 in eighteen months. I lost dead on nine stone. No surgery at all, just a very low calorie diet. My skin really wasn't that bad either. But that's what people were OBSESSED about - the skin - I would always get asked about it.
Perhaps being rich and famous makes it more difficult to find someone who really loves you for yourself and to find friends that you can trust.
