Have you gone to a LLL meeting?
I know that i have a friend who had overactive letdown and oversupply issues. She had to hold and press in on her other breast while nurse on one side due to something, i can't remember. It dulled the pain.
What is your company's bread/nursing/pumping 'policy'. Make sure you have a place to go or a place at your desk. Storage is sorted out. Make sure to bring extra clothes just in case.
There are soothie things, can't...