I find mine gives a good support and makes my back feel better when I use it correctly.
They don't sell a headrest with it, citing that if you position yourself correctly you wont need it, but if that is the source of your discomfort they sell ones that mount and look pretty close to the same Aeron family styling on amazon.
There are A B, and C sizes, if yours is too big or small this might be the source of your discomfort as well. Rub your fingers along the inside of the top of the back of the chair, how many 'dots' you feel is the size. (1 dot for A, the smallest, 2 for B the medium, 3 dots for the large, C)
(I'm 5"8 and the B one fits me well)
I sit in mine by pushing my ass as far back as it will go then putting my weight down and leaning back, seems to fit my spine groove the best that way.
It will either have the "bar" style lumbar support or the "X" style, I have the bar and place it fairly high up on its rack mount.
It also nice not to sweat on my lower back since its ventilated.
It was a nice parting gift from my last job since the facility was closing and its been good to me for at least a year so far.