What do I do about really dry damaged hair?

I tend to straighten my hair a lot and if Its not straightened it gelled and hair sprayed and the chemicals in it dry it out. My hair is naturally a frizzy curly mess, so its impossible for me to wear it natural... What can I do about the dryness? (My straightener is already ceramic and I put protectant spray on my hair before I do it) Do you know any treatments they can do at the hair place to put back the moisture? And what are some good treatments I can buy at the store?