Re: Clogged milk duct, I think...
The clog may be close to the surface, in which case it may be visible, or there may be a nipple blister blocking the outlet (also visible), or the clogay be deeper in the breast in which case you aren't going to be able to see it.
Another technique which may help is dangle nursing: lay baby on her back and dangle the breast into her mouth from above. That gives the milk flow a gravity assist.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"