Day 10 of 90 done 10% there! Need a chair.

What are we talking about here again?

i stand up and stretch for a min every 30 min
and keep a small pillow behind my lower back to push against

till i save for a better chair

A friend once told me this and it actually works. Get one of those little sticky papers and write something like "Sit straight" or something similar. Then place it on your monitor and whenever you look at it you will remember that you need to sit properly... :)

I'd recommend one of those balance ball chairs. Of course sitting too long on anything generally isn't healthy so getting up and moving a bit every 15 or 30 minutes is a great recommendation.