Not according to the Hippocratic Oath. But like a lot of oaths, doesn't mean too much to hardly anyone, which is understandable I guess. I mean if you spend 10+ years going to med school and spend thousands of $$ on tuition, then I suppose one would be a fool to not expect some sort of return on ones investment.
Yes they are. If you have a serious condition, the doctor might have some compassion, treat you and have you sign a payment plan. Emergency rooms cannot turn you away however, if you need to be in the hospital for an extended stay and cannot pay anything, they can discharge you. Unfortunately, it's all about the money.