How is the pain related to the darkness?

Revelation 16:10 And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain,

Could it be similar to?

Exodus 10:21 And the LORD said unto Moses, Stretch out thine hand toward heaven, that there may be darkness over the land of Egypt, even darkness which may be felt.

It was so dark in Egypt that the darkness could be felt.

What if the fifth vial judgment, it is so dark that the darkness hurts to the gnawing of the tongues?