Yes, when PCS runs into years it becomes more than irritating! Reading about your neck how's your posture? Keeping your spine straight may help a lot in relieving discomfort, I know it's had a positive effect on my crunchy neck. I'm thinking of trying tai chi to release tension. I tried a chiropractor but it didn't help, gentle massage and heat helped a little.

The falling unconscious episode sounds worrying, was a cause ever given for this?

I think limiting stimuli, eg limiting computer work, TV and intense conversation etc, just doing light exercise for a month and seeing if it helps. Getting mentally in the right place is important too, don't be hard on yourself, don't watch the TV news (too depressing), do some activities like easy walking, gardening, painting - mindfullness stuff, it gives your brain time off. I rebuilt a VW beetle engine it really helped my anxiety being absorbed in manual work. Good luck.