Torso pain during crunches

Has anyone ever had weird torso pain during 1-sided crunches? I did the 1st day of 30 Day Shred yesterday and when I was doing the side crunches I had a weird feeling that was kind of like gas or just something "in the way" of the crunch. I didn't get the same feeling on the other side. Would stretching help this or should I be worried about something?