Once again thanks for the info. I will ask my apothecary for some over the counter nsaid if it's possible.

The cause of the muscle tension is most likely physical overexertion and psychological stress as a result from the physical trauma. A bit like burn out. A week after the concussion i was feeling much better but not fully healed. My enviroment didn't believe i was still suffering from a concussion and let me resume full activity, including a lot of physical labour that had put stress on my neck. After a month of that i horribly crashed. And the psychological stress of it made it worse.

Over the following months my muscles started to relax but very slowly. Both my face and neck were extremely tensed. Now it's still tense but less. Im trying to learn how to relax and move on in life. I think that and with time it will get better. I agree that i can tqke a long while before the muscle is fully relqxed again