The whole idea of “Free Will” sounds like a quick excuse from the religious side because it has holes in it. If god is said to be all knowing, then he should have known that people would suffer if “Free Will” is granted to us. Here you could say that “Free Will” is such a beautiful thing and without it people would be like robots with no goals to strive fore and no point of existing so you could say that “Free Will” is worth all the suffering but then is god not evil to make a decision he knew would make our lives extraordinary but filled with suffering? Could he not do so we have a “Free Will” but a will of making and creating peace, prosperity and love? I say that god is loving to grant us the beauty of life through “Free Will” but he grants us something we never asked for and that brought suffering with it. Here you could question the fact that god is omniscient because if you say he is perfectly benevolent and omniscient would not have allowed suffering because he would know what the decision would lead to. You could then say he knew that all along but in a long shot he knows every thing will become alright, but during that period of time people still suffer and that makes him not perfectly benevolent. If you say he is perfectly benevolent then he cannot be omniscient because he would know that by giving us “Free Will” he would bring suffering. If he then is omnipotent why does he not perform the unexplained miracles as he did very often before? I here say that god cannot be omnipotent, omniscient and perfectly benevolent at the same time for otherwise there would not be any evil and the fact is, there is.
Another way of thinking of it is that there is a Devil on the opposite side of God where God stands for all love, power and knowledge and where Devil represents the evil in our world. The Devil is the one who tempts us in doing evil upon ourselves and others and if we do not believe in god and the bible we are easily tempted in doing evil. This makes sense to the extend where it is said that god is omnipotent. If god is omnipotent it is in his power to terminate the Devil so why does he not? If god is omnipotent he could terminate the Devil, if he is perfectly benevolent it is in his will to do so but the fact that he is all knowing could conclude that if he terminates the Devil then something worse than suffering and evil will happen, maybe that we people would not have a life or anything to life for. This alone could be the answer to the question of why does evil exist, but it is not my opinion and answer for there is a hole. It is said that god created the Devil as a angel who grew power hungry and became evil. This means that god cannot be perfectly benevolent by creating something that will cause suffering, or he is not omniscient for not knowing that it will not.
When coming down to it, I think that god can not be omnipotent, omniscient and perfectly benevolent at the same time. It seems as though these things have been inaccurately planned out by religious people and by sawing inaccurately planned out I mean that they do not fit together as I just argued and god as Christians and Jews think describe him cannot exist. My final answer to the question of why does good and evil exist has nothing to do with god. Every individual is like a god and that makes sense to me for every person can create, think and love one another and that is natural, as natural as hate, fear and make one another suffering. I believe that every person possesses yet unexplained energy and is in need of it when they feel down, clouded minded, nervous, stressed or lack in self-confidence with other words when the energy level is low. They then seek to gain that energy from other people in order for them to feel better by proving others wrong, winning a argument, gaining their attention or by force and then these people whose energy has been taken feel down, clouded minded, nervous, scared etc. To make all of that easier to understand my more basic explanation is that in some people there is a god in some there is a devil (and in some there are just worms =;-) and there fore people do bring each other happiness but yet suffering, it is natural and goes together just like there is no white without black. Suffering and evil is something in our human nature and it often leads to good for a person who has had suffering often rises out of the ashes and prevents further suffering ex some people why have in their childhood felt not equal start equality campaigns when they grow up. God as the omnipotent, omniscient and perfectly benevolent has nothing to do with it for in my opinion the whole thing is just a dogma which has been going on for 2000 years (in Christian religion) and from my opinion, sometimes what is most difficult to explain sometimes carries the most easiest and basic explanation, such as what I have just written in my conclusion.