 [ Symptoms ] why do i have pain in the back of my left pelvic just below the illac crest i am male and have a history of back pain [ Disease ] i am sorry to hear you are experiencing this i hope you feel better soon unfortunately it is impossible to say what is going on without a physical exam and possibly other tests such as an x ray or mri you do not say what your age is but it is important to remember men can get osteoporosis just like women among many possible causes for your pain is a stress fracture of the pelvis due to osteoporosis of course many other conditions could be contributing to the pain you are experiencing your best bet is to get an examination by a medical professional you can start with your primary care provider he or she will guide you toward appropriate treatment if necessary best wishes to you