I do not have a back problem. However, sitting in most treestands, especially "hang-stands," for an extended period will fatigue even the best back. Most stands will never win an award for ergonomic design.

Most stand seats and/or platforms, especially the hanging type:

ï€* Are too narrow in depth to allow positioning your body so that you can find the natural curvature of your spine.
ï€* Are too shallow to allow using a lumbar support.
ï€* Are too low to allow you to correctly distribute your weight to your butt, and stresses your back muscles.
ï€* Have shallow (small) platforms that play a role in incorrect positioning and (body) weight distribution.

In addition, the lean of the tree usually dictates the lean of your torso.

The most comfortable stand I ever used was my "Grizzly" ladder stand. It had plenty of platform area, I could lean the stand to obtain a comfortable position, and I used a padded rifle support that I could rest my arms on or lean forward to rest my back. It (rifle support) was also very useful for laying a loaded bow on. Someone also liked the stand; it was stolen.

Now, when I plan to sit for a prolonged period, I use my butt-pack as a lumbar support, I have two foam-rubber pads glued together to sit on, and I wear a back-support belt.

http://www2.northerntool.com/category/97632/

For real comfort, I use my ground blinds and sit in a padded folding chair.