The PDF print happens as a background task and we do not give a progress bar for it as is the case for Interactive PDF. Maybe because the file you are exporting is large and are exporting a high quality one it may be taking time. You may be better able to judge the completion once you can see the progress.
For print PDF if you want to see the progress bar then you can:
1. Open the background tasks panel (Window > Utilities > Background tasks)
2. Also there is an indefinite progress bar on the top end which shows up until the a background task is in process and disappears once background task has been exported
Regards
Javed