Prometheus was a Greek god who loved to watch over the humans, as he was the one who created them, and noticed that they didn't have the fire. The gods, of course, had the fire but saw it as a symbol of power and authority. Prometheus pitied them of course so, despite their relentless warning, he shared with them the secret of fire. Zeus, another Greek god, finds out. He has him tied to a log to sends birds to peck at his eyes every day and allows Prometheus's eyes to heal at night so that he can restart the torture.
Frankenstein, like Prometheus, brought to life a human and for this, he was also tortured through grief.