Wish I could say what that is. We've heard of finasteride-induced testicular pain, but I don't recall anyone mentioning problems in the tower itself.
Me, I still have reduced libido and don't get spontaneous erections anymore, although every so often I will have morning wood. Not every day like before, though.
What kind of pain is it? A simple ache? Or burning?
I hope it's not the finasteride in your case, but I will say that for my entire life, including pre-puberty, every now and then my (insert favorite nickname for it here) will just start aching for seemingly no reason. It's something that I've sorta taken for granted.
If your pain persists, I hope it is the sort of thing that Ibuprofen or some other pain killer would handle. Best of luck.