In physiotherapy for my tendinitis of the headdress I get a massage and then I place electrodes, without any effect … What else can be done?

Hello, my opinion on the treatment of the shoulder in rehabilitation obviously depends on the reasons of appearance of your tendinitis.
In a very general way, all our team think that the rehabilitation of the shoulder must be mainly manual (not necessarily very long sessions).
As a general rule, a shoulder that goes wrong is decentered and there is no durable solution without manual refocusing.