One breast doesn’t respond to pump

Di

I know it’s normal to have a slacker breast but I think my problem is that the pump doesn’t empty my left breast. Baby nurses from that side fine and I can tell it gets full. But if I’m pumping all week at work I usually end up with a clog on that side because it’s not properly emptied. I can usually pump 1 oz from the left and 3 or more oz on the right. Anything I can do to fix this ?