Individual Master File
You may get a copy of your Individual Master File using the Privacy Act disclosure law.
Once upon a time, there were many people who could help you decode the codes on your IMF. They have all been shut-down by an iron fist. The Justice Department uses a "temporary" injunction claiming that they are promoting scams that encourage taxpayers to evade their taxes.
Try to find someone that can help you. Otherwise you can buy software that will be helpful in the decoding process, but heed the warnings and learn how to use the law. Let the buyer beware.
And always beware of "Patriot" and "Sovereign Citizen" schemes that you cannot verify for yourself.