I can't always fix it

I woke up in the middle of the night Thursday, and I KNEW what was causing Michael's pain. It had to be his pancreas, because that's excruciatingly painful, and it's made worse by fatty foods.
I knew it, I just knew it.
So I waited until I thought he would be awake -- he's too sick to work these days, so he can pick up whenever he's awake-- and I told him.
"They've looked at that already, Mom, and it's not my pancreas."
Damn.
The kid has been in pain for four months now. It's so bad it often breaks through the pain meds. His weight has stabilized at about 135, and he can keep down bland foods. But he can't work, so he has no income, and I can't pay his bills. His roommate has offered to take over paying all the rent and utilities until Michael can work again.
As a mother, I want to fix it. I want to be able to tell the doctors to figure out what's wrong and make it happen.
When he was in Savannah, his doctors were incompetent or uncaring or both. They let him suffer and his now-ex-wife took over and advocated for him.
Now he's divorced and he's being cared for at Duke. They're good doctors and they care about him. But after scans and tests and poking and prodding, they still don't know what's causing the pain. It could be nerve damage from the radiation he had to get rid of his cancer, or it could come from the fact that he has had so many surgeries he ought to have a zipper installed in his abdomen.
But I can't make it better, and that drives me crazy.
Rob asked me the other night if all the exercise I'm getting now helps my stress levels. Maybe. I don't really know. I just want my kid to be better, He's still my baby, even though he's 33.