Have a look at this thread,
http://www.fitfreak.net/forums/2nd-generation-ge-08-present/68431-possible-lumbar-support-fix.htmlIt may help with your problem.
I had a similar problem to yours with my 2012 Jazz es, within an hour of driving away from the dealer I found the seats very uncomfortable where they pressed into the small of my back.
I modified both my seats as in the above thread, very easily done using 2 cable ties per seat and immediately found a comfortable position. The active head restraints are worked by that big lump halfway up the seat back, and the cable ties allow you to customise the position- you may still need to recline the seat slightly, but should get support for your back.
It may be worth a try, if it doesn't work for you , you just remove the cable ties.
The seat cover unzips at the back to expose the above mechanism.
I hope this helps.