I have a shoulder cat, and I think it's a good thing, not a bad thing. My shoulder cat used to try to climb me, as well, though, and that's not okay.
To train the cat to stop climbing you, do more than just say "No." You'll see your cat prepare to climb by looking up at you, moving around, getting ready to jump. This is the time to remove the temptation and redirect the cat. My cat doesn't climb a moving target, so I move, and make it obvious that I'll pet her if she jumps on on a table, counter, chair, or other place nearby that is okay for her to be on. Then I pet her, angling my body to make it a small target.
As I sit in my computer chair, my cat often jumps onto a combination of the back of the chair and my shoulder. This is much more comfortable than having a cat on my shoulder, and I really like it. My cat only jumps on shoulders with clothes (she used to sit on the ground by the closet in the morning waiting for my husband to put a shirt on), although she has erred in the past and seen a strappy tank top as a shirt (not good enough!). At a little over two years old, Athena does not jump on shoulders nearly as often as she used to, but she still does sometimes. I might have been less positive about the long-term prospects of her as a shoulder cat were she not always so small ... she's now an 8 lb fully grown cat.