Do I Need to Copyright My Music Before Uploading?

Not necessarily.

This is not legal advice, But… under the present US copyright law, which became effective January 1, 1978, a work is automatically protected by copyright when it is created. A work is created when it is “fixed” or embodied in a copy or phonorecord for the first time. Neither registration in the Copyright Office nor publication is required for copyright protection under the law.

There are, however, certain advantages to registration, including the establishment of a public record of the copyright claim. Copyright registration must generally be made before an infringement suit can be brought. Timely registration may also provide a broader range of remedies in an infringement suit.

For more information, visit http://www.copyright.gov/circs/circ50.pdf