They're called reflexive or emphatic pronouns: Reflexive means that you're referring back to the subject of the sentence. She was talking to herself. I cannot bring myself to do it. You should give yourself a gift on your birthday. Jane treated herself to a facial on her day off. For emphasis: I will do it myself. (I could say 'I will do it' but adding myself to the sentence means - really, don't help me.) The cat opened the door itself. I saw it myself. I hope this helps. I know it can get confusing when you're in the midst of it all :)

El uso es igual en español. Yo lo hago a mi mismo = i do it to myself or i do it for myself. La chica hace daño a si misma = She hurts herself. El perro hace daño a si mismo por luchar con el labrador. = The dog hurts itself by fighting with the labrador.