Hi Jenquirk,
Welcome to the Pain Mangement Forum. I am sorry to hear about your acute undiagnosised pain.
Have you followed up with your PCP? If not I certainly would. Your pain does present like a kidney stone. The vomiting could be due to the pain. When I have had kidney stones (too many times) I have always vomited from the pain. However I did not have severe stomach pain other than what one would associate with vomiting. The low back pain was extreme and as you describe like labor.
There is also esophageal spasms that can cause the extreme epigastric pain (like labor also) and vomiting. Normally one does not have back pain but everyone is different.
The important thing to do in my opinion is see you physician and discuss this with him/her. This can best be diagnosed when it occurs. Go to ER again when you first feel the pain coming on. You may have passed the stone or it may just have been missed on your last trip to ER.
Best of luck to you,
Tuck
This also sounds like the possibility of gallbladder problems. It took the doctors 3 months to figure out that my gallbladder had completely stopped working. I was on the couch in severe stomach pain 24/7 and they finally did a HIDA scan which showed the problem. I did not have any stones, my gallbladder had decided to stop working all together. Good luck.