Has the GI ever recommended a med like Prevacid or Zantac? Acid can be a big issue with steroid usage. They're are so many that are over the counter now, that it's not too hard to try. Might want to ask him about it and see if it will help.
My 6 year old Carter has frequent stomach aches as well, usually during/after meals. Our GI put him on prevacid for acid as well as an antibiotic called erythromycin that helps speed up gut motility. They think that his GI tract isn't moving quickly enough and that's what's causing his pain. We saw a decrease in pain when we started on the meds but it's still almost daily. We see GI again on the 24th of this month and they might be setting up an endoscopy to see if anything else is going on since he's still having pain.
Joshua is only 7, but we too have this happen too. We too were told to give him Zantac, but we opted for Gravol. It works instantly. If it is acid though, lemon juice mixed with water works great! Fighting acid with acid works better than only reducing it. I hope this helps.
I have been told that the steroids also mess with the natural flora and fauna in the GI. I started giving my son probiotics.
oh I forgot to add that he no longer takes anything but the probiotic, no antacids, proton pump inhibitors, (prevacid, nexium)etc.