Afrocubarico.
I have been getting the same pain over the past 2 months.
I think it maybe as I have progressed in my ability that now everything is like a coiled spring tense . I have started to video and watch myself play in a mirror . the first things I observed was how tense i look , no matter how hard i try to relax before and during practice it still tenses up .
So know I am working on relaxing my body more and am finding new ability , even though i am fully aware that a player should be relaxed to get the best out of any Instrument , during some intense practice when you push yourself is when its tough to relax.
Also I may pay some visits to a local physio therapist who works with sports injuries and is very good . I found when I cut my practice time down after a few days the pain eases .
Its very hard to keep away from these Islas at the moment though .
Ill be interested in how you go , keep us informed with your solutions .
marco