It is always appropriate to discuss your problems with your primary care physician. After you see a specialist, you can ask your primary care doctor if he agrees with the recommendations. You should be able to ask the specialist herself if you have uncertainty about recommendations. Some situations do not lead to a specific diagnosis. Some illnesses can only be diagnosed long after onset of symptoms.
It is rarely beneficial to your care for you to seek more than two or perhaps three, opinions from a physician of the same specialty. If you do get opinions about the same issue from more than one physician, and particularly if they make different recommendations, you should share this information with the physician who continues to participate in your care. It can be dangerous to your health to withhold information from the treating physician.
Your primary care physician should be informed of the outcomes of your evaluation and care by other doctors and providers.