Most of the sound you hear when you fire a 22 LR high-velocity round out of a rifle is the supersonic "crack" of the bullet breaking the sound barrier. It's not that loud and I don't think it is a danger to your hearing. In a 22 LR pistol, the sound of the muzzle blast is MUCH louder.
I have a 26-inch barreled 22 LR bolt-action. The long barrel pretty much eliminates the sound of the muzzle blast. When shooting high-velocity 22 LR rounds, all you hear is the "crack". When shooting sub-sonic 22 LR rounds, the "crack" sound is totally GONE, and the rifle is as quiet or quieter than some of my pellet guns.
So... you definitely DO hear the "crack" sound of the bullet breaking the sound barrier when you are behind the gun, at least when shooting a 22 rimfire RIFLE. With a pistol or with louder cartridges, the sound of the muzzle blast is so much louder that it drowns out the less-loud sound of the bullet breaking the sound barrier, unless you are far enough away from the louder sound of the muzzle blast (like downrange).