how can the us goverment fine me for not filing for health care insurance when ive not been notified of any such law in writting.

As Mr. Tischauser explained, you are presumed to know the law. By way of extreme example, our government did not send you a letter saying murder is a crime, does that mean you can't be charged with murder? As an aside, people who choose not to have health insurance are essentially fining/taxing the rest of us. When an uninsured person has a medical emergency, your fellow citizens end up footing the bill through higher insurance premiums and higher medical bills.  Part of the new health care law is about personal responsibility. However, for those of us who cant afford it, the Government will subsidize the cost of the insurance premium (unless you live in Florida, where we are refusing to help insure millions of mid to moderate income people for the sake of politics). 

All laws are public record and you are charged with knowledge of them, hence the old adage ignorance of the law is no excuse.