I'm having numbing pain from my hip to my ankle when i sit why is this?

Numbness hip -ankle: Numbness usually reflects nerve dysfunction. May be nerve compression, from ganglion cyst or if from herniated disc or piriformis syndrome( compression of sciatic nerve in the buttocks from the piriformis muscle, or hamstring tightness . Rarely could be mass or other process , like lyme( that should be constant ) or autoimmune -again should be constant. Follow up with orthopedist/or neurologist

Sciatica...: Hello, What you are describing sounds like spinal nerve compression at the lower spinal level about L3-S2. This is usually accompanied by shooting pain, numbness, and tingling. When I see patients in my office with this complaint I send them for a lower back MRI and a neurology consult.