Why are we charged to ask questions now if we can call our doctor for free?

Good luck. Very few doctors will answer unlimited questions for free. They need to earn a living too especially with the broken U.S. Payment system, educational debt, and business costs. Plus, generally, they will only answer questions related to a current condition/illness or treatment. Any other questions and you will be asked to come in for a visit - primarily to get an in-depth interview and exam.