By cord like lump do you mean hard? If so, I'd think along the lines of something like Peyronies Disease. This is scar tissue buildup in the penis. Trauma can happen years earlier and this occurs. https://www.webmd.com/men/peyronies-disease copy and paste that link to see what you think. But you are right. It also sounds like the primary symptom of lyphangiosclerosis. I've read one of the main things is to not masturbate or have sex to help it heal. And it does usually go away on it's own without intervention.