It may be the cast on you use, and sometimes sts will twist around the needle. After you have a couple rows done it shouldn't be a problem, the knitting will have some length and they'll stay straight. If get the loops between stitches on the first row, you're using a backward loop CO and that's what it does. Try a cable cast on or even long tail and that should help. A knit CO is easy, but with a larger number of sts they'll twist around the needle easily too; the cable CO will too, but there's a little more 'heft' to it, so might not be as bad.