I fixed my breakpoints problem by clicking the “Restore defaults and reload” button located in the “Settings” section. To find the button: In Developer Tools click the cogged wheel next to the top right three vertical dots. (Note: If using older versions of Google Chrome, click on the top right three vertical dots and then select “Settings F1”). The button “Restore defaults and reload” is at the bottom right.
Also note that it really restores defaults – you lose all previously saved breakpoints and any files you have open in Developer Tools will be closed.
I got this solution from: Chrome javascript debugger breakpoints don’t do anything?