I'm about 9 months post injury. I feel like some of my concussion symptoms have resolved but I have ongoing very problematic neck issues.

I have 24 hour a day pain and discomfort in my neck and head.

I have a lot of pressure and a sharper pain in my temples and sometimes in my sinus areas.

There is also an overwhelming feeling of inflammation, extreme heaviness and sometimes like a burning sensation in my upper neck/occipital area that seems to be stemming from two areas on either side of my upper neck but causing the sensation throughout the whole area.

I'm wondering if anyone has had experience with these type of symptoms.

I feel like there is likely a combination of muscular and nerve issues.

What have you tried to reduce any strain on your upper neck?

Any icing, physical therapy of any kind, chiro, osteo, posture changes ?

I have had subtle upper neck problems for almost 2 decades but never experienced [There is also an overwhelming feeling of inflammation, extreme heaviness and sometimes like a burning sensation in my upper neck/occipital area that seems to be stemming from two areas on either side of my upper neck but causing the sensation throughout the whole area.]

I can't picture what 'an overwhelming feeling of inflammation, extreme heaviness and sometimes like a burning sensation' can be. From what it appears you mean is you sense this in your mind, not with touching the skin and area.

I just get pinching and grating. Rarely a feeling of warmth.

I know what you mean about head pressure and sinus pressure, I've been getting it lately after I started up running again. I've started taking Turmeric to see if will help. I'm trying to practice good posture and some very gentle massage too. Computers and driving don't help, my neck crackles like an old radio!

I get the pinching and grating, but also this other sensation. It's not easy to describe it but the way I put it is relatively close. Seems to fit with some descriptions of neuralgia.

It's not that the area is hot to the touch if I touch it with my hands. It's just the sensation that I feel in my neck and head. It's a combination of this feeling plus the pressure and pain in the rest of the head together.

The one thing I know for sure is that my muscles are constantly toned and I have some nervous system issues (constantly in fight or flight).

Hard to say if there's anything else at play. Unfortunately it's just super uncomfortable and a lot of pain 24/7.

I'm doing physical therapy, icing, heat, posture work, psychological work. Hopefully something gives some amount of relief at some point.

I had some burning muscle pain & muscle spasms with my RSI/TOS/myofascial pain.
The spasms are locked up muscles that contract- pulling down & around your cervical vertebra , thus the grinding /crackling..
myofascial - Google Search

It took a long time with a very good chiro & expert PT and my own at home therapy to resolve it..and off work..

look up trigger point chart info - there are charts to locate your pain and see where trigger points might be. then info on how to manually press on them to release them.. Some you may not be able to reach by your self, the ones on the side of the neck might be near a main artery so a professional might be best for those if you have them in that area..