Why does my hair feel waxy and how can I treat it?

I don't know why but my hair always feels waxy after my hair drys from a shower. I use Pantene Pro-v medium to thick 2-in-1 shampoo or about 2 months and I also use Paul Mitchell Super Skinny Serum or something like that. Paul Mitchell helps a little bit compared to when I dont use it but my hair still feels waxy. Can you tell me why it's like this and how I can treat it?