A few minutes ago on NHK I saw some entertainment show - and there was the phrase 「きゅんきゅん」 as an answer to some question. I can not find translation for it..
"きゅんきゅん" is a onomatopoeia(オノマトペ) in Japanese.
"きゅんきゅん" denotes that someone is felt or moved someone's mind by palpitation of falling faint love.
Compare it to feeling after read through Japanese manga "君に届け", English novel "The Gift of the Magi".
Nowadays, "きゅんきゅん" also means the feeling like "kawaii".