Painful let down?

I have a 9 week old and we are EBF. He was born early & it took us a few weeks to get the hang of it, but he's doing awesome now & gaining weight like crazy. I'm loving the convenience and bonding that bf gives us, but since day 1, I have experienced EXTREMELY painful let down both when pumping and when bf-ing. It doesn't ever hurt on the side he's eating from, but the other breast gets this really really painful ache, and sometimes both beasts will feel it if he sleeps longer and doesn't feed on schedule. Anyone else experience this? It isn't a sign of anything to be worried about, right? Any ideas how to alleviate/prevent this? Btw I'm pretty large chested, 38DD when I'm not breastfeeding and have a slight oversupply. I'm always engorged when I wake up.