As far as I know no one has ever died by wishing. We die of cancer and heart attacks but not wishing. Like the gastric juices of the whale, a deep resentment was eating at Jonah. He resented the fact that God forgave and blessed these heathens. Jonah was occupied with self.
Selfishness shrinks the soul.
Notice how little Jonah had become. More concerned about his reputation than saving a city. The whole city had been saved and his focus was a vine. It was a catastrophe to lose his shade. Jonah had become a small man.