I saw the consultant this morning and it's confirmed, I do have a bad back. It doesn't require surgery at least (there isn't a surgical option for what I have). Basically it's ware and tear of the flappy bits (not his words) on one side of my back, right at the bottom.
He's recommended I see a specialist who can inject me with slow releasing pain relief stuff. I'd need to go back every 9-12 months to get it reapplied.
That of course means that I have to stop playing rugby as it makes no sense agitating it or making it even worse.