have a chip on your shoulder idiom informal
C2 （因觉得受委屈或不如别人优秀而）生气，耿耿于怀
to seem angry all the time because you think you have been treated unfairly or feel you are not as good as other people
He's got a chip on his shoulder about not having been to university. 他因没能上大学而耿耿于怀。