Remember that we're discussing chairs. Everyone's body is different. A single chair that fits everyone perfectly is almost certainly impossible to design. Even the best chair in the world can't expect a 100% approval rating... unless it's custom-built for you. (And, even then, the chair that works best today may not fit you tomorrow.)
Audition some alternatives and sell the Aeron if you find one that works better for you.
My Aeron's big problems: It is a fraction too short, and it doesn't have enough upper back support. I fixed Problem B by strapping a pillow to it with a bungie cord. Problem A still awaits its solution. I may try building a false floor (basically a sheet of plywood atop a few 1x3s) -- a wacky but effective solution. ;)
Audition some alternatives and sell the Aeron if you find one that works better for you.
My Aeron's big problems: It is a fraction too short, and it doesn't have enough upper back support. I fixed Problem B by strapping a pillow to it with a bungie cord. Problem A still awaits its solution. I may try building a false floor (basically a sheet of plywood atop a few 1x3s) -- a wacky but effective solution. ;)