I've had the same problem. Eat little bits lots of times. A few bits of something counts. I would also recommend trying to eat things with better nutritional value and less chemicals than you have listed. Try mashed potates, rice, applesauce, scrambled eggs, peanut butter on crackers, Omit things that are full of chemicals like potato chips, eggos, and deli meat. If you wake in the middle of the night, have a little snack by the bedside to eat. After my first surgery - emergency colon removal, it took me approximately 3 months until I could eat more than a bird's portion at a time. And I had been very ill with a UC flare and not really ate 6 weeks prior to my surgery. In fact, with my most recent surgery - jpouch creation... I have had the same problem. My husband would cook me ONE scrambled egg and it would take me three meals to eat it. But I eventually would get in all down. So just remember every bite counts and try to make each bite of good nutritional value.
Also get outdoors if you can and get some fresh air, even if it is just sitting or lying outdoors. And have someone take you for a car ride, bring along pillows. Anything to move a bit or just give yourself a change of scenery will help you.
Gravity works in funny ways -- here is what I mean. Now that you have some extra space in your abdomen and things have been disturbed and moved around from your surgery, it will take some time for everything to find their new home internally. Do be sure to tell your dr about not being able to control your pain -- it kind of sounds like spasms to me. Maybe a Xanax type of drug would be more beneficial.
I'm not sure how accurate this is, and hope that someone else will chime in on this one if I am totally off base, but I think I remember being told that the nerves in the abdomen area grow horizonally. Like in a band from the spine, around your sides to the abdomen. So the banding of pain you are feeling may be nerves repairing themselves and "growing back". Just a thought.
I had some really awful back pain after surgery as well. Be sure to continue to keep moving, walking, even thru the really painful days. Remember forcing yourself to walk right after surgery?
And do the deep (as you can tolerate, slow, inhale-thru-the-nose/exhale-thru-the-mouth) breathing exercises to get thru the pain. Most of us tend to hold our breath when we are in pain, or take really shallow breaths. The deep breathing really does help the pain but you have to make a conscious effort to do it, even tho it may not be comforable to do so.
Good luck to you.