You need "medical evidence" to support new claims and for an increase. I had my brother and wife write statements for me long ago. It did seem to help in my psychological claim. However, the medical is most important especially for physical impairment. Your shoulder will be almost all ROM. If you have full ROM or anything close you won't get an increase most likely. What kind of pain meds do you take? This can be basis of increased disablility if the meds affect your ability to think. You want to hook up psychological and physical issues. Vets don't do this enough, but you need medical opinions for this.