Is a person held accountable for self-talk that includes ill-will towards others, and how can one strive against the self to get rid of it?

You bear no sin for these whispers, thoughts, and ideas, for the Prophet, peace and blessings be upon him, said: "Indeed, Allah has overlooked for my Ummah whatever they whisper to themselves, as long as they do not act upon it or speak of it." The remedy for this is to ignore and turn away from them, and to supplicate frequently that Allah diverts evil thoughts from you, while occupying yourself with what benefits you in matters of religion and worldly life. You may also consult a trusted physician.