I found out that most of my neck pain was because of tight trapezius muscles. And not the upper part of it, but the middle one. Trapezius is actually a huge muscle, one of the biggest actually, and it goes from the top of your neck to your middle back. Tilting my head in various directions didn't help much, but stretching the trapezius muscle as a whole did. A correctly executed "jefferson curl" does wonders here. Hope you'll feel better soon.