theres a lot of things that you can do.. maybe you should try Long Aid Curl Activator Gel.. it works wonders for me, under a good leave in.. and finger styling helps also, you said your roots were straight? try to curl or encourage your roots to curl up with your fingers..
or maybe your hair needs protein and / or moisture, i know that my hair needed protein after the BC, and my hair wouldnt hold a curl until i did a hard core aphogee treatment.. or you could try to incorporate mild protein into your daily regime until you see improvements..
HTH!