hey, sorry don't have experience of this but maybe it's just your hormones adjusting, or breasts starting to fill again after the feed. I tried to google and did find some other people talking about it but no real answers.
If it continues I'd see a health professional, it may just be one of those things that goes away on it's own, as baby will be demanding more and more milk for a while, growth spurts to come soon!, maybe just an adjustment to making more.