Pain in left boob

I've been exclusively pumping since they were born on December 1. I pump every three or four hours. The past few days my left boob in the same spot has been hurting. It hurts to touch when it's not full and worse when it is. I massage it while in pumping but it still aches, it feels a little lumpy but I've always had lumpy breasts. I thought maybe it's a clogged duct but I'm not sure. That same boob leaks a lot so I would be surprised if it was a clogged duct. Recently I just got a shot (birth control depra Vera ) and had a horrible allergic reaction. A day after that the pain started in my left boob. Do you think it has something to do with that?? Any advice will help.