I wonder if people really ask themselves whether the voice they hear is from their brain or their heart when they are making a decision.

Do I tend to rely on a rational or irrational decision-making process when I've got life-and-death decisions to make ?

Is it a cultural, sociological, scientific or psychological issue when I need to make decisions both large and small through out my daily life?

For instance, schools taught me to use my brain, yet most movies toldell me to listen to my heart.

Why is it so difficult for myselfe to choose a university to go to, a man to get married to or a career decision to make that I'm willing to pay for someone could readwho says they can read the future through cards, stars or the lines on my pawnlm.

This sounds more natural in the US.

To analyse my own decision-making strategies would be like giving a speech on chaotic systems which would only lead to a disaster.

Well, let's put it this way : when I have a tough decision to make, my heart wouldill give me strength and, when decisions have gonego sour, my brain would confortill tell me to not tohave any regrets.

I wonder if people really ask themselves whether the voice they hear is from their brain or their heart when they are making a decision.

Do I tend to rely on a rational or irrational decision-making process when I've got life-and-death decisions to make ?

Is it a cultural, sociological, scientific, or psychological issue when I need to make decisions both large and small through out my daily life?

This sentence is a little difficult to understand. Are you trying to express that your decisions are influenced by culture, society, science, and psychology?

For instance, schools taught meI learned at school to use my brain, yebut most movies told me toemphasize listening to my heart.

Movies can't "tell" you something.

Using "but" is more colloquial and less formal than "yet" for this case. But if you want to use "yet", you should switch to "and yet."

Why is it so difficult for myself to choose a university to go, a man to get married or a career decision to make, a husband, or a career direction that I'm willing to pay for someone couldto read through tarot cards, stars, or the lines on my pawn.lm?

"career decision" -> "career direction" slightly changes your meaning, but I think it sounds more natural.

To analysze my own decision-making strategies would be like giving a speech on a chaotic system which would only lead to a disaster.

Great sentence!

Well, let's put it this way :, when I have a tough decision to make, my heart would give me strength, and when decisions have gone sourgo wrong, my brain would conmfort me not to feel regret.

Does yYour bBrain aAlways aAgree with wWhat yYour hHeart sSays?

Titles in English are usually capitalised

I wonder if people really ask themselves whether the voice they hear is from their brain or their heart when they are making a decision.

Do I tend to rely on a rational or irrational decision-making process when I've got life-and-death decisions to make ?

Is it a cultural, sociological, scientific or psychological issue when I need to make decisions both large and small through out my daily life?

For instance, schools taught me to use my brain, yet most movies told me to listen to my heart.

This sounds more natural to me

Why is it so easy when giving out advice away for free ?

The 'for free' part isn't wrong, but I don't think you need it.

Why is it so difficult for myselfe to choose a university to go, a man to get married to or a career decision to make that I'm willing to pay for someone couldto read through cards, stars or the lines on my pawnlm.

I think this might be what you were trying to say?

To analyse my own decision-making strategies would be like giving a speech on a chaotic system which would only lead to a disaster.

You could also start this sentence with 'Analysing' instead of 'To analyse'

Well, let's put it this way : when I have a tough decision to make, my heart would gives me strength and when decisions have gone sour, my brain would conmforts me not to regret.

"If I had a tough decision to make, my heart would give me strength and if decisions had gone sour, my brain would comfort me not to regret" would also work but is more hypothetical.