Had a couple of months muscle pain (neck and back just below the neck) this year. Some days it was that bad that i woke up in the middle of the night.
So I first went to a sport masseur and after 8 treatments there was still no relief, I went to the doctor who sent me to a physiotherapist.
He did something to my back and ribs and used dry needle therapy on the muscles. It went away after three treatments.
So I had already, as anyone else in the company, my desk and chair all installed for me by an ARBO instructor (someone who tries to prevent this sort of work related injuries).
What did I learn? It was not the desk or the chair nor their position. It was me, during work I keep some muscles continuously tense without knowing it (you do not notice this unfortunately till it is too late and they keep hurting).
Remedy: relax all muscles as often as you can, do exercises, tense and relax, walk to the coffeemachine every 20 minutes keep arms hanging as if you can not control them so just hang them as if you are numb, that kind of exercises.
Consult a specialist as soon as some pain starts in your muscles or joints, don't continu it gets worse to a point you might not be able to work properly, do not let this happen to you.