Mussolini was always really a left-winger and only got a reputation as being a right-winger once he incorporated a nationalist stance into his ideology... just like Hitler did as well in fact.
Let me explain why fascism is considered right-wing, even though it is left-wing because it is statist. I can explain this. :)
In Europe, everything is statist. The statists won the ideological arguement in Europe. Individualism is so dead in Europe that John Locke’s grave is cemented in and they built an iron fence around his grave so he doesn’t get out.
So, right-wing, centralism, and left-wing are relative to each other in Europe. Communism is left-wing, liberalims is centralism, and fascism is right-wing, because they are all relative positions to each other. Socialism won in Europe and 99% of the population is socialist. Fascism, in Europe is the allowance of running a private enterprise so that it can be taxed and its taxes redistributed.
Fascism is not right-wing objectively. Fascism is a statist belief system, so it’s objectively left-wing. A conservative cannot be a fascist, becasue he does not believe the government should be involved in the lives of people. Conservatives are individualists.