A friend just had them. She went to the doctors twice and was sent home with severe stomach ache both times even though it's hereditary for her too. Ended up in Casualty on morphine, which is apparently very good. She's been told to avoid fatty foods for the foreseeable and has been living off fruit and veg.

My colleague at work had a really bad case (needed surgery) and described it as a stabbing pain in the side, so I guess it's different for everyone (although she's quite a large lady so they may have had a different cause).