Most people who habitually use a keyboard end up with rounded shoulders, just look at any of your colleagues while they are using a keyboard. Looking at an anatomy book you will see just how complicated the shoulder is. It is surprising that so few people actually have problems with their shoulders. It is really worthwhile seeing a Chiropractor/Osteopath to get your posture checked out. When I saw a Chiropractor, I was surprised to be told that my posture was pretty bad. One of the reasons for my shoulders becoming rounded was trigger points in the pectoral muscles (across the chest). Having had the trigger points erased, I now regularly do a stretch to stop them coming back. This stretch is also pretty good for the muscles in the upper arm.
The stretch is as follows: Stand in a doorway, then take a step forward. Reach back with your right arm and place the palm of the hand on the doorframe just above shoulder height. Now move yourself around a bit until the arm is straight. The actual stretch is to lean forward and push your right shoulder forwards so the pectoral muscle from the right shoulder down to the centre of the chest is stretched. Hold the stretch for about 10 seconds and imagine the arm and pectoral muscle lengthening then relax and repeat for the left arm. Repeat again for both the right and left arms. When I had the trigger points in my pectoral muscles, if I did the shoulder rolling exercises I would feel/hear lots of clicks from my shoulder blades now I don’t get any.
Comment : I do this same stretch and it helps. I still hear the clicks you mention and I hope they will go away as well.