i'm a male 33 i have the same problem i checked my self did every blood test you can name ultra-sound, cat-scan, xray, you name it did it, but the doctors said we don't see any thing wrong, but i'm still in pain. im taking aspring stomach guard now it works, and i'm going back to my doctor to do more test. don't take too much aspring if you have other medical issues it might cause internal bleeding. see your doctor. Alcohol and cigarettes also could be the problem. i quit alcohol. i'll keep you guys posted. i'm 33 and that's only issue that i have cold also me acid problem.