Whats the difference between journeyman and master?

That depends on whether you are working in the union or not

If you are a union worker, master status comes after a minimum number of years worked as a Journeyman and some certification tests and classes taken etc. The union assigns this status and it determines your pay scale as well as the types of jobs you are qualified to be sent out on. The exact details depend on the trade and state.

If you are non-union, it should be the same but if you can convince an employer to hire you at master wages and responsibilitiy levels, then you are one regardless of your work experience. In essence it depends on your resume and actual skills. Just because you were hired as a Master whatever now, does not guarantee work at that level in the future.