In men, vague back pain on the right side is usually caused by prostatitis, or inflammation of the ureter and appendicitis. Inflammation of the prostate usually results in pain in the small abdomen and increased frequency of urination. Inflammation of the ureter can cause paroxysmal colic and hematuria. Appendicitis can cause pain in the right lower abdomen and vague pain radiating to the lower back. You need to go to the hospital for an ultrasound to identify the symptoms before you can judge. If the symptoms are accompanied by frequent urination, consider that the symptoms are mainly due to prostatitis, which causes vague pain in the lower back.