I'm trying to work out what's going on here

The trigger event is identical to someone's recent post.

I've been feeling under threat due to the ongoing behaviour and noise coming from a downstairs neighbour.

Without warming-up beforehand. I did a few repetitions of fast, aggressive shadow-boxing in my living room. Part of me wanted to see if I still "had it" (the ability to protect myself) - I've no intention of getting into a fight, but would defend myself to prevent serious injury.

I sensed a head-jarring sensation at the end of each punch combination, then felt a bit weird/off. This has continued in some form for most of the week.

I've recently moved home and the new place isn't great - very poor soundproofing exacerbated by the anti-social neighbours. It's very stressful and I also have to deal with working from home in a job that requires a lot of concentration and screentime.

Part of me is obsessively ruminating on the possibility that the force of my own punches being thrown and snapping in thin air at the end of their extension caused my brain to shake about in my own head very quickly. There's no way I would have worried about this in the past.

Part of me knows that my head did not move during this 'practice' and I don't believe the human anatomy is designed to be that fragile - even for TBI survivors. I'd have to be super unlucky.

Afterwards I noticed my neck muscles felt very tense for most of the day, so perhaps has caused a trapped nerve (or something similar), which is affecting oxygen supply?

I''m wondering whether there is inflammation going on too (due to the level of stress)?