1) You haven't learnt how to moisturise your hair properly.
Most people think that their hair is moisturised when it's laden with grease or oil. Uh-uh...water aka H20 is your cheapest and best-est (:-)) moisturiser. When I moisturise my hair I :
- Spray a mixture of with water and vegetable glycerin on my hair. (roughly 70% water 30% glycerin)
- Apply a leave in/ water based moisturiser,
- Finally seal with an oil e.g Castor oil, Coconut oil etc.
Also, if you're using products with petroleum, lanolin, mineral oil, or a lot of silicones, your hair will be moisturised at first, but after a few days/ weeks will become dry. Check out my post on products for more info http://thatgirlwiththefro.blogspot.com/2011/03/products.html.
2)You're manipulating your hair too much.