Flash bangs are not painful. They simply disorient your physical senses.
In my case, I was in OCS and I was attempting to lead a platoon in a military operation at around midnight. We had been sleep deprived for almost
three days. And these idiot TAC officers were really harassing me.

A surprise attack was launched against my platoon and the TAC officers
began firing off flash-bangs. Well, the noise was so loud that I could not give orders to my men
(they could not hear me above the bangs) and
we were all totally blind
(one minute it's pitch black in the woods and the next minute white flash-bangs are going off all around us -- all I
could see was "white," like when you stare too long at the sun-- I had lost all my night vision, due to the white light emitted by the flash
bangs). It was chaos and men were running everywhere.

[edit on 21-1-2005 by me again]