I get some of the similiar pains and I recently was diagnosed with endometriosis which is with your uterus. The pain is usually around the belly button but it does move around. It is much worse during periods and I get alot of pain after having sex. I don't know if you get all these symtoms but you might want to read up on it. They say some ppl think they have IBS with this cause some of the pains can be similiar. Also alot of ppl go for years miss diagnosing this. I would diffeniatly read up on it if i was you, but the only way for them to be for sure if this is what you have is to have surgery. so make sure you have alot of the symptoms. Maybe that is what is going on with you and you are just looking into the wrong system. let me know if this has helped you any.
I have pain in my left side, left hip, lower back, over right buttock, low abdominal and sometimes a 'heavy' feeling. I have been diagnosed with possible Chrohn's disease (negative) IBS, arthiritis, and have had many tests over the last 3 and a half years - ct scan, endoscopy, barium xrays etc etc. The Doc now thinks it is rheumatism!!! I am overweight (not hugely) and am trying to lose it. I did lose 2 stone a few years ago and the pains seemed to diminish. I get the gas, the bloating and the painful wind and sometimes loose stools but no-one seems to know the cause. The pain in my left side is a daily pain, the hip is worse when stretched. I also get pain in the left groin area. Please know, you are not the only person suffering all this!!!! I have been told my pancreas is fine, liver/womb/ovaries/kidneys all fine. I am giving up now and concentrating on eating extremely healthily and losing weight to see if that makes a difference.