Country is headed to the AMAs...Carrie is singing about stretchy pants... Carrie Underwood, Jason Aldean and Kane Brown will perform on the American Music Awards on November 21st. Carrie and Jason will sing their hit "If I Didn't Love You," and Kane will sing his latest single, "One Mississippi."The American Music Awards, hosted by Cardi B, air live on ABC. Carrie Underwood just released "Stretchy Pants" -- a fun tribute to holiday overeating. Carrie says, "People know that I am a champion for a healthy lifestyle, but…