Sudden pain during exercise

[positivitymonster]

I plucked up the motivation to get the yoga mat out tonight and embarked on a mild to moderately difficult yoga class. When doing a standing forward fold with legs apart (I don't know the names?) I suddenly got this severe pain in my upper abdomen, at the bottom of where my rib cage meets in the middle. I would describe it as a burning pain and an intense feeling of discomfort as though something had moved out of place. I could feel a spasming/rippling for a few seconds, and then like something moved down and the discomfort subsided. The pain continued, decreasing in severity, for a few minutes. Now it's only a little sore in twinges but I'm mostly just freaked out as I never want to experience that initial feeling again! I've tried to google it for some more information on what went on but I just can't find the right words to bring up anything helpful.

I'd be overjoyed if anyone could please shed any light on this for me! Thanks!