Guys why did Yirim went through a surgery again? Is he sick?

The.. Birth the surgery was the birth of his baby

Yes he was sick. He was going to temporarily stop figure skating to get surgery. This was the original reason why he missed the Olympics. However, during his hiatus he got pregnant so the public mistook the fact he took a break was because he got pregnant.

It's a surgery for his hormone imbalance that caused him to quit skating in the first place. Though I wished they explained what kind of surgery is done for that.