Thank you everyone for your replies.
Koala I did try the Z thing on my chair and it did ease it, it does seem to go from one side then the other.
I have been dx with Degenerative disc disease, spondylotic disc bulges, facet joint degenerative changes in my lower lumbar levels. as well as SFPN
Maybe that is the cause? could that cause sciatica?
I also get a lot of thigh pain but it is a the front and side of my thighs.
It is really a pain in the butt (pun intended) not being able to do the things I want to do, like cleaning my house and going shopping. not that I like doing housework but I do like to see it tidy, I have a good vacuumn cleaner - a dyson with a power head so that does help it is not so back breaking.
It is so good being able to talk to you all knowing we are going through smimilar things.
My doctor has said to me all that can be done for me now is to treat the pain, so I will just keep popping the pain killers.

Thanks for your help.
