Welcome to OCF, Ann! Im very sorry you are having trouble with your tube feeds. You are correct, it can be tricky to get everything stabilized after rads and chemo.
Try to think of the feeding tube only as a temporary tool to get you thru some rough months. Most patients with feeding tubes experience some difficulties at first. Most patients have a lack of support to teach them all the ins and outs of using the tube. These difficulties can usually be eliminated by slowing down the absorption rates, taking less in at a time, and/or watering down the formula. If you use a pump to administer the formula, slow down the rate. During the feeding you should be sitting up and remain still for at least a half hour after the feeding. If slowing down the rate, watering down the formula, and sitting still dont help then as a last resort it could be the formula itself. There are hundreds of different prescription formulas available. You might need to chsnge formulas. Ive gone thru this and tried several before I found the one I could tolerate.
Take some time to review the following link. It has tons of info about feeding tubes.
Feeding tubes/nutrition from main OCF pages Let me know if these things work. Good luck!!!