3 weeks old

My son is now 25days old. I pump one breast almost exclusively because it was damaged and hurts too much when he latches (pretty much have a hole in the side where milk comes out instead). my fiance will give him a 4oz bottle of breast milk and immediately when he's done he acts like he's still hungry. if I offer him my nipple he will nurse for another 5-10min before falling asleep. he wakes up after a couple minutes and wants more. he never throws up like he's eaten too much and he's not a chunky boy. I'm just wondering if anyone else has experienced this or if this is something I should contact his pediatrician about.