Flat ironing my hair..HELP!!!?

My hair is thin and naturally curly( mixed Korean and Jamaican) and when I flat iron it after I wash I spray John Freda leave in conditioner and dry it, it's fine for the first day but the next day my scalp is really dry and itchy. I just wondering is there a good product I can use that will stop the itching but keeps the volume and bounce of my hair like when I don't use a product..I can't use grease, serums or the smooth and shine products because they are to heavy for my hair and right now I use Pink moisturizing lotion but it makes my hair look greasy with no volume or bounce. Thank you!!