please use an adjustable height, adjustable back (depth and height), short arms (if you use arms). I haven't read all the other posts (yet) on the recommended chairs, but if your back is hurting you should think about using a better chair! The speaker last week at our guild meeting was a Physical Therapist who addressed many of our aches and pains... he spent a lot of time going over the chair-choosing guidelines. At first glance, there are many great suggestions on this thread! Protect your back!! Stop and stretch occasionally... even get up and walk around for a minute or two!