Shampoo in a dream signifies cleansing, some part of you is being cleansed and cleared for the new to arrive. A fresh perspective is present – you are washing away the dirt or darkness for a clean and pure way of living. The message is about purity of thought, mind, and spirit, including the well-being of emotions. It could be about one or all of these aspects of yourself.
There is an innate symbolism of washing away the impurities and dirt in your life. Due to the dream-link in your mind, this can also portray a new spiritual awareness and understanding. Your hair is physically/geographically located by your crown chakra, the energy wheel or portal symbolic of a connection to divine or cosmic consciousness (the divine/your higher self). Right now, deep healing and cleansing is occurring in your life.