Time and fullness

So I am pumping for my son who is in the nicu and needs it. I know that they say I should only be pumping for like 30 mins or until I get the very last drop. But if I pump for 30 mins they are still way to full and get engorged within like an hour. If I pump till the last drop I’m pumping for like an hour and a half. My son is a week old and I’m pumping about 160-200mls each time and I try and do it every 2-3 hours. About 1000 mls a day. Iv been doing warm wet towels before and Massaging but when they are engorged it’s so painful to massage it.

Any kind of advice would help thanks ladies❤️