I'm currently trying to put together a theory about WHY we (as social animals) have this 'inborn sense of right and wrong' as you put it. When a trait is 'common to all men' then it should serve a purpose in our species, or it would have been 'bred out': Evolution does not favour useless bodyparts. The eyes of cave dwelling animals (that live in complete darkness) serve no function. The ancestors of blind cave fish DID have eyes, but we only see rudimentary small eyes that serve little to no purpose. We could say that we are watching a transitional form of animal here: From having eyes (its ancestors) to having no eyes, since moving into caves meant eyes are pointless appendages.
Robert Wright's book The Moral Animal shows well-documented evidence that this doesn't just include physical bodyparts: Behaviour is also influenced by natural selection (evolution). As he puts it: 'Our emotions are the executants of evolution.'
I think I have finally found an answer to why we all share this trait, this 'sense of right and wrong.'
If you want to read the complete theory, you'll have to wait: I haven't finished it. I still have to see if there is evidence that supports what I 'm about to summarise here, but having the well-documented social studies of Wright as basis is a good start.
What is characteristic about 'immoral behaviour'? I think the answer is going to be that it is destructive to society. Stealing and murdering are clear examples. We as a species benefit from living in a society more than from living as solitary animals. It is in our best interest to display behaviour that supports our society, rather then damage it.
Sharing with others creates a bond with others. We see this in south-american vamire bats (Desmodontidae), that 'altruistically' share the blood it has sucked up during the night with other less fortunate bats to create bonds. It does however expect to be fed in return when he himself hasn't been able to find food.
We display the same social behaviour: We help others and expect something in return. The selfish behaviour (survival of the fittest) is not lost; it is integrated in our social structure.
Stealing is taking something without giving something in return: It goes against the 'rules' by which our selfish side is incorporated in society. People are willing to share, but only if (even in the long run) they get something back for it. 'Something' can be money, attention, respect, a place in heaven, friendship, food etc.
Immoral behaviour leads to loss of respect/status (at least this is what I'm basing my theory on). It consequently leads to a reduced chance of reproduction. (Would you date a murderer or, more important in this matter, would you have a baby with him/her?)
People who DO uphold the values that are required to have a complex society are more likely to reproduce. This 'inborn sense of right and wrong' (which might have started very simple, like in the vampire bats) is then passed on to next generation. We are more inclined 'to do good' because all (or most) of our ancestors did good.
By the way, do you know what happens with the immoral bats that refuse to share their meal with generous (but now hungry) other bats? The generous bats cut their social ties with the non-sharing bat and let the selfish bat fend for itself. You can image that this overly selfish behaviour is not good for its chances of survival, let alone reproduction. The opposite of immoral behaviour, moral behaviour, will be increased in later populations.
In conclusion, the moral values we talk about are favoured by evolution, because it increases our collective chances of survival. Our 'inborn sense of right and wrong' is a necessary 'tool' for accomplishing this and is based on very simple (and relativly selfish) motives.
NOTE: I am always referring to examples from nature because I want to make it clear that we are just another animal species. Many (and I'm convinced ALL) of the 'divine' traits that we are ascribed are not put into us by a creator or god, but are logical consequences of how life developed.