This is not an exhaustive list but it includes many of the uncommon conditions that may be causing your pain. You might consider showing it to your doctor with the idea that you can’t make a diagnosis if you don’t think about it:
Conditions Associated with Back Pain Only
Midline Disc Bulge, Protrusion or Herniation
Ankylosing Spondylitis/Strumpell’s Disease
Vertebral Compression Fracture
Spondylolisthesis, Isthmic or Degenerative
Degenerative Lumbar Subluxation
Some Conditions Associated with Lower Back and Leg Pain
Spondylolisthesis, Degenerative
Degenerative Hip Joint Arthritis
Facet Joint Impingement
Extraforaminal (Far-Lateral) Disc Herniation
Narrow Sub-Articular Gutter
Lateral Recess Entrapment Syndrome
Thoracic Disc Protrusion
Ischio-Gluteal Bursitis
Sacroiliac Joint Pyarthrosis
Intradural Sacral Nerve Root Metastasis
Intradural Periradicular Ossification
Viscerogenic Pain
Conditions Associated with Leg Pain Only
Retroperitoneal Tumors
Inferior Gluteal Arterial Aneurysm
Psoas Muscle Rupture with Hemorrhage
Hypogastric Arterial Aneurysm
Posterior Compartment Syndrome
Trauma from Fetal Head During Delivery
Conditions Associated with Hip Pain Only
Broken Hip
Degenerative Hip Joint Disease
Hip Joint Bursitis
Hip Joint Infection
Slipped Capital Femoral Epiphysis
Lumbar Disc Herniation, Far Lateral