Not exactly bad behavior, but...

...I'm curious why my cat does this lol. Ever since I got her 2 years ago, every night and morning she snuggles under the covers with me, which isn't bad until she starts kneading her claws into my neck in the same part of my neck every time until she goes to sleep. I don't really mind it, I think it's the cutest thing (even though I have little claw marks in my neck every morning ), I'm curious though why she does it. Would it have something to do with when she was nursing?

I didn't think it was possible, but I think my neck has gone numb in that area...

Yes - keep her claws trimmed! Yes - it's something they do when nursing. When they're older, it means they're happy and content, and it's very comforting to them.

This is an instinctual comfort behavior, they mimic when nursing from their mothers as babies. It is not uncommon while sleeping for them to dream and mimic this behavior as well. They will make a suckling noise and move their paws while sound asleep. It's definitely a sign of love and comfort as well, they share this behavior when they feel safe and comfortable. It is best to trim claws regularly, however at 2 years old it may be difficult to start now. Soft paws are another alternative.
It's awesome that you don't reject her even though she may unintentionally scratch you. You can always redirect her kneading into clothing or pillow, so it's not hurting you.

My cat very rarely kneads, so even if it is a little painful, I still love it. She is very very quiet, and usually even when she purrs I have to put my ear almost on her back to hear it. But when she's kneading I can hear her purring from a couple feet away. It makes me think she's feeling comfortable and safe.

My kitten Squeak does the kneading thing too, but she never puts out her claws. She rarely uses her claws when she is on people. She's so sweet!

Well that's good to know that it means she feels safe and comfortable, I have started clipping her claws (which oddly, she doesn't mind too much just kind of goes limp). SOOOO much better!!! My neck will no longer be sore

And it's funny, because she gets her mouth right up to my neck, so afterwards my neck smells like cat breath