If I didn't learn much in my PhD program, should I do a coursework-based masters in the same field?
If you want to try making a few changes, to see if they have a positive effect, before deciding, here are some ideas:


Each semester, take one of the classes you're interested in.
Before reporting the week's results to your advisor, anticipate what he might prescribe as the next step.  Write up your ideas about next steps each week, to show to your advisor for his opinion and/or green light to go ahead as you proposed.
Set aside one or two hours every day for literature research (reading of papers).  In the beginning it might take you more than a week to get through a paper, but it will get easier with practice.


Please note, your distractibility is something you could talk over with a doctor (general practitioner), if this is a significant problem for you.  There are a number of things you and your professors can consider trying that might help.

If your doctor screens you and finds a noticeable difference between you and the general population in this regard, you can get some assistance with management of the distractibility from your university.