Hi guys! I just started on my first job, which is pretty much a desk bound job at a computer. However lately after the job I've realized that I have upper back pain coming particularly from both sides of my spine along my upper back, near the base of the shoulder blade. I did a bit of searching and think its possibly a strain on the trapezius muscle, the 'tail' bit of it near the end between shoulder blade and spine.

Have included a diagram with the area of pain marked out roughly in blue, hope one of the image link codes work. My question is why is there pain from this particular area? (Most back pain literature I saw deals with lower back pain or pain in the shoulders) are there any exercises or stretches that will ease the tension specifically in that area of the trap, because it's kinda hard to stretch? Any help will be much much appreciated! Thanks!