I’ve never had a focus ring jam before.
On my 24-105mm, the zoom ring will sometimes not let me zoom past 70mm (or return from being zoomed beyond 70mm). The odd thing about it is that it works sometimes and it doesn’t work other times. If it is jamming up, I’ve found that pointing the lens downward will allow it to zoom past 70mm, but not without a strange mechanical clicking noise. It’s working just fine right now. No jam. No clicking. I’m beginning to think it might have to do with all the jarring around it gets in my camera bag as I travel around. And I don’t have all that much padding in my camera bag either. Perhaps it’s a pressure point in how it’s positioned in the bag.
Since I can not speak from personal experience on the focus ring, perhaps one of these articles online would help. Seems like plenty of people have had the same problem. If it doesn’t come unstuck by itself soon with external persuasion, it looks like you will probably have to take it apart: