Yes everyone has to pay an entrance fee to be allowed in the Shenandoah National Park.
Shenandoah National Park started charging an entrance fee on June 1st 2018 to pay for improvements with the infrastructure and visitor experience.
The entrance fee to Shenandoah National Park is not that expensive and only costs $15.00 per person, $25.00 per motorcycle and $30.00 for cars.
The entrance fee is good for up to 7 days before you need to pay another entrance fee or you can buy a yearly park pass for $55.00 which is good to enter the Shenandoah National Park all year long.
Then you just need to get a new park pass once the year is over to visit the Shenandoah National Park again the next year.