ADHD

Whoah, I have this, except it also extends to my jaw area and under the chin, maybe even back of neck. People touching there will make me gag, but clothing, hair, and even air can trigger a gag response from me. I usually associate this with being anxious, particularly used to be bad with travel anxiety or test anxiety or public speaking. In rare cases, I've associated it with eating something bad or sickening (including junk food or food poisoning or eating too much).

Sorry, I don't have a cure. But it did start happening less often after I hit my 20s. maybe since I got more used to travel and graduated and stopped needing to take tests. Still happens a few times a year.

Since mine is related to gag reflex, actually gagging/retching kinda resets it for me, and often makes me feel slightly better after a bit.

Hyper aware of what? Like that it exists or something touching your collarbone?

For me it's from the collarbone up to the chin, especially the front. I can't stand having t-shirts with collars that sit anywhere in this zone. I remember as a kid the collars on my t-shirts would be soaking wet because I would hold them in my mouth to keep from touching my neck. My solution is to wear low cut or V-neck tops. I sleep on my side on two pillows, this means most of my neck isn't touching the pillow very directly, just the upper part and on the side. Also don't like the 'double chin' touching my neck when I look down so I have been 'mewing' for decades to avoid it. I only learned it's called mewing recently, and no it doesn't tone your jaw (not what I was doing it for anyway)

I kind of get this, but it's not specific to any particular body part. Usually it's if I feel something slightly different than normal, like a fingernail that's just a little bit too long, and I will unconsciously fidget with it for the next hour or two.