pain on right side of abdomen

Hello,
I have had two flare ups of a pain/discomfort around the edge of my ribs on the right hand side, and down my right side from the ribs down to the hips. The pain seems to radiate into my back sometimes - though I am prone to back aches anyway, so this may unrelated.

The first time the discomfort started was in April this year. It came for a couple of weeks, and I had been doing some running - not usual for me! - and I felt it under my ribs on the right side so I thought at first it was either stitch related or muscular. I also had occasional loose stools, but nothing dramatic. It didn't go away though so went to the doctor. He tested liver and kidney function with a urine and blood test and an ultrasound of the area. Results came back normal.

Symptoms faded away after two or three weeks. Then, about three weeks ago, they started again. Same area. This time, the pain is sometimes more like a numbness or even a surface itch, though I can feel a deeper discomfort. I also had bright red blood in my stool fairly regularly - though that has stopped now and could be piles, which I’ve had before.

Went back to the doctor, and he tested my stool for bacteria and my breath for H. pylori. Everything negative again. He wants to try a colonoscopy next - he says he suspects colitis. I was due to travel overseas, so just to see if he could zap it, he gave me a course of Azithromycin - 500mgs for 3 days. Symptoms are unchanged though.

My question is, do my symptoms sound like colitis? Is it more likely to be one type than another given the location of the sensations? Are there other possibilities? Could these sensations still be muscular? I am training (very gently!) for more runs and I have to say that symptoms seem to get worse when exercising. A nurse friend said that the location of the pains could mean it is an inflamed diaphragm and the pain could be radiating out from there. And can I rule out liver and kidney problems given the test results?

What do you think?

[LexTex]

Well I was recentlyI having similar pains but on my left side.  I got an x-ray of the area and found out it was a blockage of gas and stool.  I was also tested for the H pylori and all that good stuff and it came back negative.  An ultra sound didn't see this either.  Try getting an abdominal x-ray.