If you think sitting up straight is the answer to back pain, think again. It actually puts more stress on your back. Growing up, we were told to "sit up straight" -- not because it's better for our health, but because it looks more productive. As it turns out, sitting up straight (i.e. 90-degree angle at the pelvis) is actually harmful in the long run. We've known this for a while -- since 2006, a