Oh G, this sounds like a nightmare, your neighbours are playing basketball against your wall? In the early hours? I just don't know what the f is wrong with some people? Who does that??
I do get/have had pretty much every symptom and feeling you've been talking about on here and I wish I could say I have found a miracle cure but for me the best cure is staying away from people and having peace and quiet and avoiding stress - which you can't get with arsehole neighbours and all this picking a course stuff you're doing at the minute.
I do agree with Skep about the pressure to engage with 'society'. My problem isn't that I don't like people or interaction, as such, but I want it to be good quality, meaningful interaction that doesn't tire me out or leave me wanting to punch a wall and that's what I find difficult to find. My friend has started reading a book called 'Quiet' by Susan Cain which is apparently about the power of introverts. I haven't read it and my friend only just started it but I thought it sounded interesting.
I have been doing this little yoga sequence for my jaw pain which I thought of when you mentioned your jaw muscles being so tight; I might have mentioned this before, I'm having de ja vu! Lol I'll put the link at the bottom.
I think being this stressed out is very adult; so many people are experiencing this. I honestly think we're at a really weird tipping point where all the 'stuff' we've been encouraged to buy and all the 'work for your dreams' stuff is actually doing us more harm than good and some of us (me!) would be happier pottering about in the garden and not talking to anyone

Ear muffs and ear plugs work wonders for my son and I use them sometimes when our arsehole neighbours' dogs are barking for hours so I hope that at least they help a bit.
I wish I could wave a wand, G. Sounds shitty. I hope it starts to lift and feel a bit better soon xx xx Keep writing it down! I like to read how you're doing, even though I wish it were easier for you at the minute
https://www.youtube.com/watch?v=NbItEmN16jw