As I initially posted a while ago, I should clarify some things!
I have'nt done much of the things described above (i.e. heavy carrying, overhead carrying).
Yet the tightness remains. It is not very painful and clearly functional but its bugging me enough to keep looking for a solution. I can trigger it quite easily for example by bending sideways (bending to the left is no problem, bending to the right I feel the tight spot right away)
Or when doing pushups if I stay in the bottom position. Scapula depressed and squeezed together I feel the tight spot and a little pain right between the shoulder blades on the left side of the spine.
I do not have Neck or Arm pain! In the summer though I have a lot of headache, which always feels like coming from the neck.
Recently I did Barbell Overhead Shrugs and it gave me shoulder pain on the left side (where the tight spot is) pretty quick...
Luckily it was not bursitis but I guess had something to do with the supraspinatus!
Also I noticed that my left scapula always makes a grinding/popping sound on the ribcage somewhere near teres major on the upward motion of the overhead shrug.
Needless to say that I stopped doing overhead shrugs two weeks ago and am lucky to be shoulder-pain-free again.
But the Situation is bugging me.
As a rock climber especially I hate it to run into shoulder problems every 6-18months.....
would be great if you could share some insights!
#edit
Oh and I nearly forgot
my general physician told me a while ago I had a "flat back" and that my right shoulder is lower than my left.
Which shouldn't be surprising as my right leg is about 0.5in shorter
#edit
I dug up some x-rays a orthopedist had made back in 2006 when I had subacromial bursitis in both shoulders (alternating). No idea if my posture changed since then, hope the pics helb!
thx!