Wait.... What components? You bought the frame used and built it up?
Have you checked the dropout alignment and the derailleur hanger? You need to find a shop that has the tools and the mechanic that knows how to use them. It is a long shot but if everything else is perfect it could be the hanger is bent or twisted and that is what is causing your problem.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk