Mondors Cording?

I noticed a weird swollen vein last night which extends from under my boob to the bottom of my rib cage. It feels like a hard sort of worm & is very painful. Consulting Dr Google it seems to be something called Mondors Cord, which people usually get 2 weeks after breast surgery. Mine was in August 2015. Has anyone else experienced this or know why it might have happened now? It’s weird knowing that new & horrible stuff is still going on in there over 2 years after surgery. x