I hope you get a good answer because mine is doing the same thing! I have fine, thin shoulder length hair, and I do color it. I thought maybe that was the problem. I also switch shampoos often. I got a clarifying shampoo to try after my stylist suggested it, but it didn't really help. My husband has dandruff and he suggested I try head and shoulders. For some reason, that worked, but my hair felt fluffy or something afterwards. I used it for about a week, then went back to my other stuff and the problem went away. It happened again last week and for the moment is gone. It feels sticky or greasy. I blow-dry my hair, and it seems like it won't dry when it happens. It is very heavy on top, if that makes sense. All I can come up with is my water. It is horrible! It is drying out my whole familys' hair and I have quite a bit falling out. Hopefully you get some good suggestions!