What Does Severe Pain In The Pelvic Girdle Indicate?

I have pain in the pelvic girdle after almost any work, I have scoliosis which is worsening. I have had the SEED operation for my Prostate Cancer. My PSA was negligible 2 months ago. The implantation was abt 8 1/2 yrs ago. I have had relative few UTIs. I do have residuals. I am imponent both urinary and GI. I basically have no control. I have increasingly been falling from a sitting position or when I turn too abruptly when standing up. I feel I lose balance. I don t have a great amount of pain unless I hit something going down.