I have heard that there are some prescription-strength anti-gas meds. I might ask about them, if over-the-counter ones aren't working.
There are a lot of anti-spasmodics you could try, but they are very hit or miss. They either work for you well or not at all. So if you get one and it doesn't work, try something else (don't give up!).
I have heard good things about pain managers; I'm sure they will have more ideas than even us!
BTW, do you have constipation or diarrhea, or just the pain and bloating and gas?