Hair goes crunch when air drying?

This only started happening recently. I dyed my hair a few months ago and my hair was fine. But lately when my hair is wet it feels like straw just at the roots. But when I blow dry it feels fine? What is worrying me most is when I air dry it, it feels crunchy? But it's strange, when I put my bristle brush through it the crunchiness dissapears. I don't use products when air drying my hair. I'm going to dye my hair again tonight (i have to, or not face the public) is it safe to do this? What's causing the crunchiness? Should I do anything to my hair before dying it tonight?