가슴이 뜨끔해요 · 가슴이 뜨끔했어요 · 가슴이 뜨끔한 (+noun)
to feel a pang of guilt, to be stung (by a remark)
Example
거짓말을 한 게 생각나서 가슴이 뜨끔했어요.
I remembered the lie I'd told and felt a pang of guilt.
Word parts
뜨끔하다 describes a sudden prick or sting, like a needle; here it's a sting of conscience.