I was thinking it would be very hard to hold a baby for breastfeeding post op, but pumping would be more doable.
I don't know how full you will get before you can pump again post op, but that extra fullness & swelling will make for more discomfort and pulling on the surgical areas.

Does the surgeon &/or OB/GYN have any thoughts about breast feeding and surgery?
Perhaps call a lactation center and ask them about concerns with surgery& post op reocvery in that area of the body.

You could also keep pumping and toss the milk that may have the stronger drugs in it, then after x amount of days/weeks it should be safe again.