The car is a manual.
No warning lights.
You are driving along, say in 3rd gear, but it happens in all gears. You depress the clutch to change gears, up or down. The gear stick will not move and you get stuck in that gear.
If you double the clutch and force the gear stick, it will change gear sometimes. More often, you have to pull over. I am trying to establish what the problem is, what the solution might be