break your neck to do something

break (one's) neck

To put forth a great deal of effort. I've been breaking my neck trying to get a passing grade this semester, so failing by two measly points is incredibly frustrating. Don't break your neck trying to please these people—they'll never appreciate it.
See also: break, neck

break your neck to do something

exert yourself to the utmost to achieve something. informal
See also: break, neck, something