Only time I ever had uncontrollable hiccups that lasted for more than a day is when I had a burst appendix. Never had pain just an upset stomach and the uncontrollable constant hiccups that would not go away no matter what I did. I was just going to sleep it off over the weekend but my girlfriend at the time insisted that I go to the ER. Docs say I wouldn't have made it to the end of the weekend. Docs were amazed I had no stomach pain, just the hiccups and some acid reflux.