It's not even the first time Sistar or Soyu herself wins no.1 on music programs but fans are very curious why Soyu cries during her winning speech at M!Countdown today with their duet song "Lean on Me" with Kwon Jeong Yeol.In regards to that, Osen reaches to Starship Entertainment to find out why. According to the agency, "Soyu is in a state where her waist has been hurting a lot so performing and winning no.1 is very thrilling and extra overwhelming for her."Soyu then expresses her thoughts through a Twitter update,In fact, at today's performance, Soyu is indeed looking not in shape. She is not in her usual bubbly image and appeared very calm. It turns out that Soyu is suffering a severe back pain.Fans then express that they indeed noticed Soyu's not in good condition today and comment, "She really looks sick today but she still manages to perform very well. Congratulations.","Please take care of your health.","Don't feel pain in the future."