Worshipper, thanks for the reply. Certainly the pain I feel is localised around the SI joint areas. There does seem to be a built up of 'gritty' feeling hard tissue which is tender to the touch and my back is stiff and sore when i bend forwards and also when sitting. I have no pain when i move my legs, walking and running are fine, it is only when the back is activated.
I was reading about a condition called 'chronic muscle hardening' which office workers can get through prolonged periods of sitting which i've done for the past six years!
Thoughts anyone?
chris