I was riding home from the grocery store with a pretty good load on the rack, and when I shifted (or tried to) from the middle to the smallest chainring as I started to climb the steep hill on the way home, the pedals suddenly stopped turning and I found that a couple of links of the chain had gotten jammed between the two chainrings instead of shifting cleanly onto the small ring. I could NOT get them out, so had to walk, pushing the bike, the last 3/4 mile home which was quite embarrassing to say the least. Does anyone have suggestions for how to get the chain un-jammed (it's in there tight!), or should I just take it to the shop?