I like plow, shoulderstand and fish for the base of the neck area and trap ridges extending out to the actual shoulders.
Cowhead pose is good for the actual shoulder joints where the arm bone connects to the scapula/shoulder blade. So is doing a standing forward bend, interlocking your fingers behind you and taking your hands as far away from your lower back as you can. That will get the area between the shoulder blades as well.
If you can grab your feet in lotus while doing fish, pull on them bringing your elbows to the ground and both knees to the ground and lift your chest up at the same time, that is one of my favorites for between the shoulder blades.
Otherwise, the various spinal twists are great for for all of these areas, too.