Recently I've started getting a strange sort of back ache. It seems to be caused by sitting down very odd. All is fine when I'm sitting (it gets uncomfortable after say ten minutes and i feel the need ot get up and walk around)), but when i try to get up it's agony and i have to pull myself up with my hands and then i struggle to walk for a couple of minutes because my lower back is so painful. General walking around is fine, lying down is fine and not painful (but the usual uncomfortable tossing and turning to get comfy). It's just sitting down. Sitting at my desk at work is a nightmare. It's been going on for a week now. I'm sure it's not my posture, because I'm careful not to slouch generally and this week have been making extra effort to sit properly. Anyone got any advice?