In the beginning life is filled with consciousness but it is the body that determines how that is used. In the course of evolution the body changes but consciousness does not. As the body changes consciousness is directed to to create new possibilities. Consciousness needs direction and in the beginning these directions are given by the natural needs of the body. Much later a shift occurs and the mind/ego takes over or begins to dominate the natural directions of the body. It is at this point that the body will do what it is told regardless of wether the new directions are sane or not. When directions given to the body turn out to be based on insane or false beliefs then suffering in one or more of its many guises is what follows. This suffering is not dissimilar to a law of physics like gravity; the suffering is a natural consequence of believing something that is not true. The similarity to a law of physics or science is because no matter how many times we run this experiment of believing something that is not true the result or consequence is predictable and will never vary. This is a serious problem and the results of believing things that are not true can be seen all around us and all over the world. There really is no other problem, all human problems have their origin in our capacity to believe things that are not true. To correct this problem it is useful to identify all the things that are believed that are not true. The easiest way to do this is to notice the natural beliefs of the body, that is the sense beliefs of the body or the way the body naturally exists in the world; breathing, touching, tasting, hearing, seeing and smelling.
I am writing my reply to Kite's comment here
Yes without the meaning embedded in beliefs sensations become like clouds drifting across the sky. What is interesting is that these sensations which are actually quite nebulous can turn the nebulous into something concrete or into absolute suffering. We are addicted to this process of turning the nebulous into concrete because the more we do it the more real ( it seems) the world becomes but more importantly it is the ego/belief entity which has no substance or actuality which is able to deceive itself into believing that it is real and does exist. And pain in all its forms is a great convincer of this.