My son is 6 days old and 2 days ago I noticed a lump in my underarm. It is not painful or red but I'm worried that it could be a blocked duct. I suffered mastitis terribly with DS1 and I'm really worried that it may develop into something serious. I'm hoping it may just be while my milk is coming in it's aggravated something in my underarm, so thought I'd put it to all of you on here. Any advice would be great! Do you think it could just be something simple related to my milk coming in?