So I both run and do weight training and have been for many years. One thing I've noticed is intense shoulder or pain on my right shoulder once I've done about 10 km. I did 20 this morning and managed to complete my run but my shoulder hurt pretty intensely for the last 5 to 10 km. I stopped a few times to stretch out the shoulder and tried to consciously be aware of my posture and look forward and run as upright as possible. The pain almost immediately subsides once I stop running. During my run I can barely lift my arm over my head because of the pain however currently tonight I have no issues. Anyone experience this? Can't figure out what the issue might be that caused this. No major changes in my running routine and this just started happening in the last couple of weeks.