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

Disc Degeneration

Midline Disc Bulge, Protrusion or Herniation

Lumbar Sprain or Strain

Facet Arthrosis

Osteoporosis/Osteomalacia

Lumbar Osteoarthritis

Rheumatoid Arthritis

Kidney Stone

Ankylosing Spondylitis/Strumpell’s Disease

Isthmic Fracture

Vertebral Compression Fracture

Abdominal Aortic Aneurysm

Hyperparathyroidism

Paget’s Disease

Spondylolisthesis, Isthmic or Degenerative

Degenerative Lumbar Subluxation

Vertebral Osteomyelitis

Epidural Spinal Abscess

Anterior Meningocele

Arachnoid Cyst

Tethered Spinal Cord

Intraspinal Lipoma

Occult Spina Bifida

Some Conditions Associated with Lower Back and Leg Pain

Herniated Disc

Degenerated Disc

Spinal Stenosis

Spondylolisthesis, Isthmic

Spondylolisthesis, Degenerative

Degenerative Hip Joint Arthritis

Synovial Cyst

Arachnoid Cyst

Intraspinal Lipoma

Facet Joint Impingement

Lateral Spur Formation

Extraforaminal (Far-Lateral) Disc Herniation

Narrow Sub-Articular Gutter

Lateral Recess Entrapment Syndrome

Spinal Tumor

Sacral Fracture

Thoracic Disc Protrusion

Ischio-Gluteal Bursitis

Sacroiliac Joint Pyarthrosis

Intradural Sacral Nerve Root Metastasis

Intradural Periradicular Ossification

Meningocele

Viscerogenic Pain

Abdominal Aneurysm

Conditions Associated with Leg Pain Only

Diabetic Neuropathy

Retroperitoneal Tumors

Retroperitoneal Hematoma

Inferior Gluteal Arterial Aneurysm

Hysterectomy Trauma

Psoas Muscle Rupture with Hemorrhage

Hypogastric Arterial Aneurysm

Sciatic Entrapment

Posterior Compartment Syndrome

Tarsal Tunnel 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

Stress Fracture

Developmental Dysplasia

Perthes Disease

Slipped Capital Femoral Epiphysis

Irritable Hip Syndrome

Rheumatoid Arthritis

Lumbar Disc Herniation, Far Lateral

Sacro-iliac Joint Arthritis