Why not go to a chiropractor?
That's what I did, turns out a lot of my issues were due to a pinched nerve on my L5 ( very lowest point on your back) near where your hips are..
I even had a rib on my left side out of place that was causing me a lot of pain (which I thought was stomach related and due to my "kidney failure")
I would get pains on my hips, stomach, back, and even upper back and neck.. all due to some misalignment. I had a few adjustments and my back is MUCH better now and my pains went away in my stomach and all around.
Go to a Chiro and get some X-Rays, it's cheap, fast, and can save you A LOT of grief... they might be able to tell you EXACTLY why your feeling these odd pains.