In simpleton terms everyone has a reason to live and that reason is their God. If not then explain how it is not .
I've bolded the crucial word there.
In one respect, yes you are right. You COULD refer to someone's primary motivation as their "god" - although, note carefully the small "g" rather than the capitalisation that refers to the Christian god, that differentiates a physical being with its own thoughts and motivations from a mere inert physical subject.
I may say "money is my god" - I doubt I would ever say "money is my God" unless I truly revered it and thought it was worthy of worship.
But the question really is: why use "god" in that sentence at all? You'll find that generally only those who have a religious belief in a sentient deity will use the word "god" in that context - and then it tends to be in a perjorative way. Those who do NOT believe find the qualifier is unnecessary, and will simply say "everyone has a reason to live", full stop.
I would tend to agree that pretty much everyone does what they do for a reason - even if that reason is as nebulous as "it makes me happy". What I find curious is why you insist on shoehorning the word "god" into the mix. Perhaps because.....
Now the life chooses I need to make is whether to be a pastor and hope I can get a paycheck like Olsten or should I dictate my life to something more meaning for the world maybe something on Physics.
...you have been raised - indoctrinated? - in faith so much that, despite your doubts, you would still feel more comfortable becoming a pastor and spending your time in comforting delusions than branching out into the real world?
You are only 14 - you've a couple years yet to go before you even have to start thinking about study choices for career choices. And even then, its rare that any decision is final. My advice would be not to sweat about what you will one day be, and at the moment take an interest in anything and everything. Its not a binary pastor/physicist route, you could be a doctor, an archaeologist, a travel writer, a dustman, a car salesman, a lawyer, a historian, a soldier.....
I guess the best advice I can give to you is to find something you enjoy, are enthusiastic about, and consider how you can make a career in it. Far better to do something you enjoy, than (for example) to study for a career in the church teaching about something you don't really believe is true. THAT would be an easy way to an unhappy and stressful life.