Pain right below rib cage

Maybe the rib pain is costochondritis?

I Always get pains right below the rib cage and then down my right side as well quite frequently. I was diagnosed with UC but was told this type of pain is usually associated with Chron's disease and not UC? Other than that they told me it is more than likely due to inflammation in the transverse colon, which would mean I also have inflamation in my acending colon as well since I get pains there. I have heard since UC should start at the recum and move up that there is a possibility that i might have Chrons or Chrons colitis. Whether it is UC or Chrons I think the the pain is a sure sign of inflammation. Perhaps yours is really mild and it is only after you eat and you stomach is filled putting more pressure up against your colon that is also slightly swollen and inflamed? I typically get mine late afternoon or evening when I do get them so my timing is somewhat on par with yours, it just isn't always after I eat like you.

I saw my GI on Wednesday coz of similar symptoms. The only difference is that I developed a day after I saw him dull pain right below the left rib cage. When I googled it, I found several causes, some of which apply to me as GERD, gastritis and IBS. I have long standing GERD (16 years), gastritis and IBS.
As for the diarrhea after lunch, this is exactly what happens to me. I get severe cramps and abrupt onset of diarrhea. I can have up to 7 explosive foul-smelling watery bms in less than 2 hrs and for which I take Imodium. After Imodium kicks in, I get severe pain in colon and intestines. When I told my GI that these symptoms occur after eating, he asked whether they disappear if I don't eat, I said they become less. He said that this was inflammation and confirmed it upon examination. I was prescribed rifaximin 550 twice/ day for 10 days in addition to my Crohn's meds.
If pain persists, call your doctor.
Take care :)

I've been on Entocort for 3 years now. It has been a life saver. However, I won't recommend taking it for such a long time as I can't get rid of it.
Good luck with it :)