having a headache;  racking one's brains;  troubling over something
 being painfully-true (e.g. reprimand);  making one's ears burn;  striking home (e.g. remark);  having an earache;  feeling pain in one's ear
 one's weak point;  one's sore spot;  raw nerve
 to go through a bitter experience;  to get into trouble;  to get hurt;  to feel pain
 headache inducing;  vexing
 to go through a bitter experience;  to get into trouble;  to get hurt;  to feel pain
 one's weak point;  one's sore spot;  raw nerve
 being painfully-true (e.g. reprimand);  making one's ears burn;  striking home (e.g. remark)
 there, there;  kiss it better; (lit.) pain, pain, fly away
 itai-itai disease;  mass cadmium poisoning in Toyama Prefecture starting in the 1910s caused by industrial waste