My jenday has these long prickly looking things around his neck and head. are these new feathers that are growing in or are the old ones that need to be plucked. I don't want to hurt him if they don't need to be plucked and he can't do it himself.

Yup, those are pinfeathers. What you're seeing is the keratin sheath that surrounds the developing feather. They can itch and make him uncomfortable, and you can gently try to preen them off, but be gentle with it. Chances are he'll let you know if he doesn't want you to do it.

it does hurt him...will they fall out or grow in on their own or could this potentially become a problem? Thank you for you response

What I do with Pita is I gently take the sheath between my thumb & 1st finger, and just squeez it. You'll feel it break, that makes it easier for the bird to preen it off. Also frequent showers are good. It helps to soften the sheath so it isn't as irritaing to him.

Be carefull though, like Nate said, they will let you know if they don't like it. The reason they may not is if you go to close to the skin, it's more sensitive there.

They will eventually fall off as the feather matures.