Butt Gives Taylor Swift?? Suddenly Packing More Back

Taylor Swift's ass will NOT be contained -- the thing has been busting out lately, and looks great, but also looks, ummm ... different.

Taylor's lady lumps were majorly on display at the iHeartRadio Awards over the weekend as she showed up in a skintight black bodysuit. We did some deep research, checking out a bunch of Taylor butt shots from the last year ... and she's definitely shown some growth.

Butt pads? Squats? Who knows?