Pain on right side just under rib cage

Are you constipated? The intestine loops just there on the right and you can get trapped wind there, that moves when you are active.

gas? could just be like an air bubble or something that works itself out once you start walking?? maybe try taking an antacid before you go walking, or drink a bit of fizzy water to get some burps out?
just a thought...i don't know why you would consistantly have air bubbles before a walk, but maybe it's an anticipation kind of thing?
clearly im not a doctor...i just know that sometimes when i get pains like that, an antacid makes me burp and relieves that bit of trapped air.

Pain on the right side could be liver, gall bladder, or appendix related. Pain on the left side could be stomach or spleen. Either side could be small intestine or colon related. Since blood flow is reduced to the abdominal area during exercise so it can be shifted to the working muscles, it could be any of the organs being irritated by not having as much blood flow. It could also be a shift in hormones during exercise that causes a decrease in digestion during that time. It could also just be the muscles getting warmed up because you are using core muscles while walking. I'd recommend seeing a doctor to rule out anything serious (polyps, gall stones, etc.) and if they say it's nothing then try to find other forms of exercise that don't cause the pain so you aren't suffering from it.

I have gallbladder disease and will probably have to have mine out. I will get pains in my right side under my ribs when I eat things that are too fatty, lots of caffeine or any food that might inflame it. I'll have this pain for a couple of days until my gallbladder's inflammation goes down, usually by watching my diet and taking ibuprofen. I don't have this "under the rib pain" all the time, but it can get rather annoying. Try eating less fatty, watch the caffeine, take ibuprofen and see if that helps. You should see a doctor regardless just to be sure.

I used to get what I believe you are referring to quite often when I was overweight and didn't do much. I believe this is your diaphragm or similar breathing muscles that are working harder than they are used to and so build up some lactic acid and cramp. I believe the pain goes away when you are walking because the muscles are getting warmed up, you're taking in more oxygen, etc. It's kind of like how your legs will be stiff at first, but then start working better after a little movement.

I have the same thing on my right side under the rib cage. Its only when I walk and I walk alot. Even short distances can be painful.

I have had a similiar pain before on my left side and that was when I was either sitting (at work only) or walking. I went to the doctor about it and he said that I had damaged the muscle that surrounds the rib, a condition called Costochondritis, apparently commonly caused by coughing. The pain went away on its own after a month or so but now that it has returned on the other side I'm not so sure if this is the right diagnosis!

When I walk too much or run after I've eaten, this happens to me. It happens on my left side, but it's right under my rib cage. I always chalked it up to eating too soon before moving.

If you had gallstones, you'd know it. It's a pain like no other. Doctors put it up there with kidney stones and childbirth as one of the most painful conditions you can have.

More than likely it's gas. If it only occurs when you walk, then you might try things like sparkling water, gas-x, running a few minutes before you walk, things like that.

If it persists, or occurs at other times, you might want to get it checked out.