Pain Near Clavicle

I have pain in the front part of my shoulder near the clavicle. It is not the bone itself, but feels like a tendon. It hurts most when the arm is straight out to the front, as in the top plank position of a pushu or burpee. Researching what it might be but haven’t found anything that describes it.

Didn’t happen suddenly but over time. Using ice and nsaids with lighter weight dumbell work and high reps.

Any ideas on what it might be and what I can do to prevent it, rehab it and so on?