Relying on shoulder during any sort of sensitivity drill is not a good idea. This is a big mistake wing chung guys do, they use shoulder tension to keep their arms stiff so the punches glance their arms. In Taiji, as a beginner, I did same thing. Eventually Peng (ward off energy) will become natural and you don't need shoulder tension.
I would suggest Zhan Zhuang, and lots of stretching and movement. I suppose you could go to Acupuncturist. But I would see what you can do, try to disperse the tension. Rub it, slap it, stretch it, do some bagua, chi gong, whatever