I will tell you as woman 33 years old, I got diagnosed with Ankylosing Spondylitis by my PCP only 2 years ago, when I started having severe back (SI joint) pain when I was 11. It would come and go, and I was a waitress. It continued to get worse, I would literally not be able to walk some mornings. I would CRAWL to my kids bedroom (this is at 30 sometimes) Lifting my leg was EXCRUCIATING pain, I was in such extreme pain all the time. I was on medicade and the docs there are few and far between, to say the least. I was seen by a doc at a "low income" doctors office, she told me that I was just a "tired and over-worked mom" . She would prescribe me medication, but then wanted me to seek physical therapy. I couldn't afford it, so years later after dealing with a ton of pain, I got a physician, sent to me (I believe from God) to help me. He diagnosed me with AS and I got steroid shots in my SI joints. I cannot tell you how much it helped. Unfortunately, the inflammation has moved to my neck now, I will say, it is not NEARLY as painful, but equally annoying. They seem like they don't believe a younger woman in back pain. I am not a drug seeker nor have I been on any narcotic medication for any length of time, but I have been to the ER several times due to complications from this disease. I am sorry to here your situation, ask them for further testing.