Breast infection/ breastfeeding

Linda
Hey 
So I stopped Breastfeeding my son and started to Pumb milk, because he has digestive problems
This week, I woke up with painful lumps all over including my upper breast and under my armpit... I read on the internet and it said Breast infection 
Did any of u have it? And what did u do?
Which doctor I'm suppose to go to?
2) doctor told me to keep giving my son formula for 6 month ... what should I do till then???