Sciatica describes pain that travels along the sciatic nerve — from the lower back, through the buttock, and down the leg. It can feel like a sharp shooting pain, a deep ache, tingling, numbness, or all of the above.
What most people don't realise is that "sciatica" is a description of what you're feeling, not an explanation of why it's happening. The nerve can be irritated in different places — a disc pressing on it in the lower spine, tightness in the piriformis muscle in the hip, or compression further down the leg. Each of these needs a different approach.
Treatment that doesn't start with a proper assessment is just guessing. Which is why so many people try exercises from YouTube or generic physio advice and don't get better — the approach doesn't match the actual cause.