1. When someone scolds or berates you for something that they don't like.
2. To harass with the intent to break one's spirit.
- When I ask you if you settled that dispute with the IRS, I am not just trying to bust your balls. I am trying to help.
- cf. There is a way to castrate a calf, instead of cutting off the testicles you break them. To "bust your balls" is to turn them from a bull into a steer. Properly directed harassment can have a similar effect on humans.
3. ( ... ) it seems the slang broadened out to mean anybody who puts another person down or gives them a hard time. Now it is reference between guys and girls and has a general "put down" connotation. Another derivation of this term is "bust my chops".
4. If you were to "bust my balls" you would be having a right go at me about something.