Update on this issue.
The pain in the shoulder is still there. Haven't seen a doctor yet, because the pain isn't too bad, so I hoped it would go away,
The pain is the worst when I wake up. When look in the mirror, I see (and feel) a little bump at the location where the pain is. Looking at pictures on Google I think the exact location is the AC joint.
If I massage that location, it relieves most of the inconvenience.
Now since about 3 weeks I also have a pain underside my left elbow, which doesn't go away. This feels more like a muscle tear, or nerve, but since it all starts spontaneous, and doesn't go away, I start to worry about a bone disease.
Is this a possibility?