Where does my last name(s) come from?

Question:

Where does my last name(s) come from?

------my dad's parents last name is Behrens (isnt that from england??)
------my last name is Rotchy (it once was spelled Rotschy<--not sure if that's exactly where the s was.)
------the only thing i know about my past is that i'm the great-great-great- (too many greats) grandaughter of -----Admiral Lord Nelson.
basically i would like to know what country my ancestors/last name originated from. or atleast an idea

Best Answer - Chosen by Asker: Where YOUR names come from, is completely depending on the birth place of your ancestor with the name, who immigrated. In order to verify this (or your link to Admiral Nelson), the only reliable way is basic research tactics. Begin with YOU, work back a generation at a time, and be sure to verify your work with some sort of documentation.