All tests from routine physical show healthy/no diagnosis per doctor. she wants me to come in to explain the results, should i be charged for the followup visit?

Yes: Charges are for a doctor's time and advice, regardless of the medical issues involved. How charges are done is usually based on local customs and any applicable laws. In general, insurance companies make doctors charge for each visit, instead of paying doctors a big amount for the initial visit and paying zero for the follow-up visits. It also makes for simpler accounting to charge for each visit.