Tried the pulse-massage setting on the showerhead to get some relief from the shoulder pain. It's surprisingly effective. The entire water output is concentrated into four heavy pulsating streams with a separation of about 3.5 cm. Combined with near-50°C heat (new hot water system is regulated to 50°) it's a good localised massage. I also employed deep finger pressure massage to the shoulder tendon nexus below the collarbone. Some ome the pain is from a pinched nerve, most is reflected pain from the tendons.