An intensive pronoun is never the subject of a sentence. Never never ever ever.
Myself play the tuba in a polka-metal band.
I myself play the tuba in a polka-metal band.
The first sentence is incorrect because it uses myself as a subject, lacks an antecedent, and kind of makes the speaker sound like a caveman (who apparently loved intensive pronouns?). The second sentence is correct because it includes the antecedent I, which is the subject of the sentence and the word that the intensive pronoun myself emphasizes.