Would be I get old? My side is too chill...(**I'm not sure my translation is correct ^^;) 옆구리가 시리다 is Korean idiom. It means "I'm so lonely, I'm feeling lonely cause I'm alone. not a couple." If you're a couple, you would walk arm in arm with your lover. Then you couldn't feel any chill on your side. So, Koreans say like that. I hope I helped you through this~~~