Is the hadith, "The martyr feels no pain from death except a sting, like the sting of an ant," authentic, and what is its meaning?

The martyr does not feel pain upon being killed, except like the pain of a pinch. This is because Allah makes it easy for him, elevates his status, and dispels the illusion that his pain is greater than that of a pinch. This aims to console and encourage people to fight in the way of Allah.