1. ouch for sudden pain something hurts physically comes out on unexpected, you have pain but have no idea where it comes from, eg: i hit my funny bone. ouch r u ok ? also can show your sympathy that you feel something or show your concerned . 2. emotional pain i didn't get the job . ouch ~ she told me that she isn't interest in him . ouch ~ your cooking isn't great . ouch, you know that . 3. it depends on the voice and in a funny way to say ouch . if child share they upset things to you don't respond as ouch , ouch is normally act to adult . 4. depend on your work place , it's ok for the small team . don't say ouch in a large company. if your boss/ someone higher status level gives you feetbacks or performance review, better to avoid it .

funny bone 尺骨端，麻筋

Ouch! How to Respond to Physical or Emotional Pain in English

very useful. But Chinese people never use "ouch"2333

funny bone