I have 3 cats whom were taken from their mother too soon. Tiger, Mylo and Panda Orson. When Tiger and Mylo were little, they used to suckle on blankets, but now that they’re 3 and 1, they’ve outgrew this. Panda Orson on the otherhand, has suckled on blankets and bathroom rugs since I brought him home, and still does to this day. He’s also 1 now. They never suckled on me, but now that I’ve brought Charlie home, (he came when he was about 2-3 weeks, now he’s around 5) he likes to suckle on my ears and hair. I don’t have any kittie hickies on my neck luckily!
Like Caroline said, I agree that the cats do it for comfort because it’s what they did with their mom, and when they were with their moms, they most likely felt safe, warm, and loved.
If your kitten’s kneading and sucking on your ears or neck hurts, you could try redirecting where they can do it. Perhaps let her do it on your arm, or put her on a fleece, or any soft blanket and maybe she’ll do it to that instead.
I’ve looked into the Catsifier but they’re all sold out!
Good luck with your kitten!