In reply to Jennifnfe:
To an extent it is a right of passage, I suppose that hanging all my weight on one hand is little different to someone of a similar weight to me standing on my fingers, I don' t know anyone that would do that voluntarily..
I also find climbing on juggy holds painful, more so than half pad crimps. I use a nail file or sandpaper to thin my callouses and also a lanolin based cream to keep the soft which helps avoid cracks, splits and pinching.
When climbing steep terrain on jugs I concentrate on avoiding overgripping and avoiding a fully closed grip that can cause pinching, whenever possible I prefer to use a more open hand grip on 1st and 2nd pads.
Training is all about specificity, If I wanted to improve my endurance for swinging around on steep terrain using jugs then I would do lots of swinging around on jugs on steep terrain. But I much prefer technically difficult style climbing so I just accept that I am not able climb on such steep terrain and focus my time on climbing problems that are challenging enough on a lesser angle when climbed on slopers and small edges.