Thought is definitely created by you, there is no question about it. Thoughts represent your involvement, participation, response and reaction to a given person, moment, situation or circumstance. Thought is your creation. Thought does not come from anywhere else, and what comes from anywhere else does not stay with you. You are only expressing yourself.
Thoughts are your creations and are the outcome of the natural responses of your mind, emotions and senses in relation to the outside world and to your own desires and needs.
Therefore, the spiritual traditions have always spoken about maintaining a positive mind, a positive thinking pattern to overcome self-generated and self-oriented thoughts. You have to eliminate them to bring in new thoughts with which you can live.
Despite having a wealth of guidelines and instructions, you are unable to change yourself due to your own nature. That is an indication that everything is self-generated. In yoga, there is the concept of pratipaksha bhavana, to counteract a negative expression with a positive one.
9 August 2015, Ganga Darshan, Munger