That did happen today with the F chord!! I couldnt do the F at all. AT ALL. Then I tried the "baby/cheater F" by just not doing a full one and leaving that ring finger off and playing that as an open string. I couldn't do that either. Not even close. But I kept trying ...all day. Eventully I could do the cheater F and now all of a sudden I can do the full F. Not quite consistently but I'm getting there. Such a good feeling to "get it" after so many hours of work. I suppose it will be like that with everything related to guitar playing. :) I'm loving every second of it.