Getting stretched rows! Please HELP!

[DancingQueen]

Hi.

I'm making a straight scarf as I am not a very experienced knitter, and I keep on getting my rows stretched out in between them. I'm using the normal knit stitch so basically when i do a row (the squiggily up and down row thing), and i then go on to the next row, the space before the row is stretched out and you can see all the kind of plait like looking stitching that you are not supposed to see.

Please help as I really want to make this good and it doesnt look very good at the moment!

Thanks!