erfahren = to find something out by being told about it, e.g. "Ich habe erfahren, daß er verheiratet ist" (I hear he is married) (And yes, it also means "to experience") herausfinden = to find something out by being told about it OR by trial and error, by looking things up etc., e.g. "Ich habe mir ein neues Handy gekauft, aber ich habe noch nicht herausgefunden wie es funktioniert" (I've bought a new mobile, but I haven't found out yet how it works)

to experience and to find out or discover.