Help! Irritation on nape/lower scalp area

hiya, I haven't logged on here in awhile but I need some advice. this has been happening for awhile now but I'm not sure why, but sometimes on my nape but slightly higher where adult hairs grow it gets super itchy and irritated, when I scratch at it, it burns or stings. Also, sometimes I noticed when rubbing my fingers through that area sometimes there's small bumps? only like 1 or 2 though at least that I can feel. I had thought this could be due to infrequent washing (although I would never go longer than a week) but even with more frequent washes same issue. Not really sure what I can do to help this so I need some advice but i'm also curious if anyone else experiences/experienced this? thank you for reading.

I’m not sure why, but that’s the area that gets most irritated if I use a shampoo that gives me a reaction. It can take a couple of weeks to settle back down.

Otherwise could there be something rubbing against your scalp, like a collar?

See if you can use mirrors or a camera to investigate. Do you see any redness? When you scratch the bumps, do you notice any bleeding or scabbing?

I had a similar problem and I believe I had some sort of fungal infection:

https://i.imgur.com/CRjSA1nm.jpg

Not to worry, some Nizoral (ketoconazole 1%) shampoo cleared it right up. I also make sure that my hair is completely dry before going to bed; I'm inclined to think that sleeping on wet hair led to this issue.

I've had a similar problem in the past and I decided it was because when I washed out the conditioner there might still have been a trace of it left in the hair, and being wet it sort of settled in the area you mentioned.
Since conditioners (and shampoos) are supposed to rinsed out, if you are slightly sensitive to any ingredients in them that would create the irritation.
So what I do now is make sure to give that neck area an extra last blast of water in the shower once everything is done. I haven't had a problem since. :o