What is the original source of 'Stress'?

Is it too much work? Is it multitasking? Is it traffic on the road? Is it failure? Is it fear of the unknown?...

While, it could apparently be any or all of the above,  I have a feeling there is something more fundamental that is the original source of stress.  It is 'lie'.  The lies that we tell others and more importantly the lies that we tell ourselves.   Recall a moment when you felt completely stress free. It would invariably be one where you didn't need to lie to either yourself or to some one else. 

We observe that whenever we have to keep up our image in a social situation, we feel stress, because, image is partly a lie (or half truth). 

When we are stranded in the traffic, we somehow believe that 'others' have created this situation for us and we are not really a part of the problem. This is a lie. 

Denial is also a form of  lie and when we are in a denial mode, there is invariably stress. There is a power failure, when you are watching an interesting cricket match on television. You feel extreme anger and stress for some time before you cool down and make adjustments (transition from denial mode to acceptance). May be, you will switch on your old transistor radio and just listen to the commentary.

An important question arises. How is 'lie' handled in our brain? I guess, each lie needs to be stored in a designated position, well indexed in our brain. This is because, when we need to back our lies some time in the future, we need to be able to quickly process all the related chain of lies and conjure up a consistent story.  Hence, every lie-chain is a separate system (or a model) in itself.  That's why it looks like brain needs to spend a lot of energy and space in protecting or supporting a lie-chain. 

(Mark Twain's quote: You don't have to remember anything if you never lie!)

Does brain always know that it is lying? Some times, a lie is deliberately thought out and output by us. At other times, unknowingly we may lie (this is lying to oneself) and only later realize it was a lie. When we understand or realize that it was a lie, the associated lie-stack is released from the memory and we feel relaxed! 

Questions: Is misunderstanding related to lie? Is understanding better than misunderstanding, because it is more efficient? What has simplicity and  efficiency got to do with truth?