Thank you for your question. Palvic pain has many causes depending on your age and sex. it s good most of the tests done are negative ultra sound. colonoscopy and bldder test Other causes of pelvic pain may include 1. kidney stones cystitis Pelvic inflammatory disease low lying appendicitis hip joint arthtitis prostatitis for men low back pain can radiate as pelvic pain Although you have done tests a repeat at different place for second opinion is always important For colonoscopy request for biopsy since it wil show if there is pathology in the colon If still negative then other tests are necessary Good clinical medical examination by a doctor. 1. Urinalysis for microscopy and cytology 2. stool for ova and cyst. Occult blood 3. Ct scan abdomen and pelvis to rule out masses and fluid collection in the peritonium and pelvis. 4. MRI 5. Full haemogram to rule out infection by raised WBCs 6. infections such as typhoid (widal test) Treat ment will be very important depending on the out come of investigations 1. analgesics to releive the pain 2. muscle relaxant in case of muscle spasm Diazepam