I have caught my 5 year old son in many lies. he lies often and completely makes up stories.?

Not afraid to communicate that didn't even make sense. This sounds like typical attention seeking behavior. My guess is both parents are very successful and therefore very busy.

There are two possibilities.

1) there's something going on either environmentally (someone bullying him or hurting him) or biochemically

The second possibility is he's lying to entertain himself or get out of trouble or for attention.

Assuming the later is true (first verrify the former is not) here's what you do. You start a rlcp-- REAL LIFE CONSEQUENCE PROGRAM.

That is two parts

- Reward him when he's telling the truth and administer a REAL LIFE CONSEQUENCE for lying. The consequence should be that everything he says for the next 24 hours is treated like a lie. Rewards should start small and go to big

It's time for a parenting class, folks. What you've got is a child who's afraid to communicate with you.

This is likely due to knee-jerk reactions where you immediately pull out some kind of punishment to try to get ahead of errant behavior. Keep that up and as a teenager, you'll really have your hands full.

My parents often told me "We'd rather hear about your mis-deeds from YOU, rather than your teacher, neighbor, the police, etc". When I DID disclose such, there was no punishment, per se. Rather, they spent time talking about it, and asking questions, and explaining why that was not good behavior, and more importantly, why it's better to behave differently.

Yes, parenting like that DOES take more time and energy, and often repeated discussions. The upside of that is you'll have open communications with your son (for the most part), because he won't fear you going ballistic for every little infraction. THEN, if he ever comes to you with something REALLY terrible, you'll have a better chance of intervening.