The paintballs break open upon impact, and generally cause very little pain. What pain is experienced is more of a stinging sensation from the paintball's impact against the skin or through clothing. In general, the stinging pain goes away after about 30 seconds. Of course, the closer you are to the muzzle of the gun, the higher the velocity of the paintball when it hits you. Thus, more pain may be experienced when shot at close range rather than farther away.