[Dark_Swan]

Are you pumping more than you have to? Is there a small leak? Cup needs to make a good seal (oil on chest), look for small cracks at cup edge and hose ends, look for small pin prick hole in tubes, put a few drops of oil into the intake of the pump to lubricate the seals/valves inside the pump.

Many women have trouble balancing growth, one breast grows faster than the other. I wonder if this is because they pump with one hand only, that is maybe the constant flexing of one chest muscle promotes better blood flow on that side.

yeah that actually does make a difference.