Doctors Conspiracy?

[JohnDoe2K]

Is it true that some doctors don't treat you as they should, why they do it?
I don't know about USA, i am in Europe and when i came to my doctor and told her that i feel this and that she said its nothing to worry about and written it down in my card, but when i requested her to write me direction for MRI scan she never did, saying theres no need etc, and when i speak about other problems i have she said like they don't give crap its don't worth treatment... Well i guess they have like 40 patients per day, but when i insist on taking MRI scan because of headache she dissuade me from taking it, saying its probably nothing to worry about...
Well heres when i got really suspicious, when i run out of my medical insurance and came to her start speaking about same problems and suggested to take MRI scan she said nothing against it, even suggested to take scan of rest of my body parts that she called not important in the past, of course for my own money that is. Even written me direction, but didn't stamped it.

So heres the question that keep bothering me, why she never wanted me to take MRI scan which worth around 50$ when i had insurance, did it somehow cost her own money when then write directions for patients with insurance?
I asked my mother and she says doctors get some amount of money each month and when they send patients with insurance to MRI for example they remove cost of this from that money and whatever left in end of month they can keep to themselves, is that true?