Need a little help with Surnames:
I have a Josepha Johnson that on her birth certificate her mother is Maria Christoferson and the death Certificate say Wigdahl. She went by Josie Hagen but I see the same birth date on records of death, birth, social security but I see both names used Johnson and Hagen along with mother maiden names of Christoferson and Wigdahl.
I see this also with names on the other side of the line. I have a Johan Larsen Kværnstuen where half the children used Johnson and the other used Kvaerstuen.
I'm so very confused! Any help?

If they are Norwegian.. the childrens last name would be their fathers name followed with -sen or -datter. For example... the Johnson last name would mean "son of John". The Kvaerstuen might be the farm name from where they came from. Here is a link that explains this a little better. It confused me at first and I had a hard time finding ancestors from Norway. Good luck.
http://www.nndata.no/home/jborgos/names.htm