This is our favourite pose before going to bed in the evening, since it gives you a lovely relaxing feeling and assures you a sweet sleep in the night.
In generally, gomukhasana (cow-face-pose) is an excellent pose to relieve tight neck and shoulders or you can just practice it whenever you feel tired, tense or worried.
Everybody is unique and not all of us have the flexibility to touch with our hands behind the back. And this pose is always easier to those people who have long arms! But no worries, you can use a stripe or anything similar to connect the top hand to the bottom hand.
Happy practice - allow yourself to explore, relax and let go!