My mother always speak lying. She thought and imagine she is right

Hello Anon

Thank you for writing.

Many people think what they think/say is always right. It could just be the way she is or she may have some sort of personality disorder - we don't know her, we can't say. Perhaps you both are just different personality types who don't get along.

Regarding her headaches - these can be caused by stress, dehydration, fatigue and many other factors. A checkup with her doctor is a good idea.
Best,
Susan