It matters when you are pumping, and what your expectations are. Wait about an hour after nursing. Or, pump halfway through a predictably longer stretch. Or, pump one side while the baby nurses the other and try in the morning. If you pump instead of nursing, and your baby is effectively nursing during some of the day, you may collect anywhere from 2 to 8 ounces per breast.
Some breasts release milk more quickly than others.
Thorough emptying will signal the breast to make more milk faster. Research shows that mothers make from to 2 ounces per hour per breast. Milk left in the breast signals the breasts to make less milk. Do not go longer than 5-6 hours without nursing or pumping. Stop all pacifier use.