Thanks for your response gcoe.

About the perception of pain - I've had the same thought at first. But the clue for me at the time was that the pain was not "just there" lingering as often seen in the "pain for the sake of pain", but rather is induced by a physical activity, and seams to follow an inflammation-type pain pathway more or less(as reported, not as observed though)

Well that's certainly food for thought about tendinosis.. That's pretty much an answer to what bothered me from the start, because of the time-frame (11y). therefore RICE would actually sound counterproductive here.. However as one of the goals for the shortest period of time (several forthcoming days) was to decrease pain flare-up after last workout, even some neural analgesia or even a placebo effect would hopefully be of some use. Whatever outcome will be valuable, though, in deciding on further options.

Didn't have the chance for a full postural analysis etc., but the observations so far suggest he's pretty well balanced, e.g. no excessive shoulder protraction or int. humeral rotation, no excess kyphosis and fwd.head, no complaints of pain, stiffness in the neck. Though I agree a closer look would be surely beneficial.

Wikipedia reference-linkMRI is really expensive here, so I kinda doubt he'll be up for that anytime soon, though sonogram might be an option then. I will suggest that then.

Thanks again for your ideas and suggestions, really helpful and appreciated