a chip on one's shoulder 不能译成“某人肩膀上的木屑或芯片”，它是一个习惯用语，可以意为“根深蒂固的不满，耿耿于怀，怀恨在心”。      

【例句】
He has a chip on his shoulder for not being born into a rich family.
因为不是出身于富裕家庭，他耿耿于怀。

He's always picking up fights with everyone. He seems to have a chip on his shoulder.
他总是找人打架。他好像对什么不满。