Spooky, I have my hang up or partial obstruction at my old stoma site too.
I had a CTscan and x-ray with contrast in addition to my pouchoscopy in July. I discovered that at top of my pouch there is a difference in it's size and the small intestines size. I forget which one is the larger. The abdominal area I thought was small intestines leading to my j-pouch was my j-pouch! I have a large pouch. I don't know what size it is supposed to be but mine is large. There isn't much distance between the adhesion old stoma site and the top of my j-pouch. Sorry if TMI but I can actually feel a hardness in this area at times.
It's either a clogging above the pouch or something's getting stuck in the pouch causing a backup into my small intestines, which includes my old stoma site adhesions. It could be some of both. And while all of this is happening the water is getting absorbed from the excrement thus causing thicker harder to pass stool. It's very painful to pass even after it's unclogged. I know this is gross sounding but I could not figure out where all the excrement was coming from the last bad time. I passed substantial amounts of firmer stool in one day than I ever remember doing since I've had my pouch take down almost 4 years ago. Afterwards I have to eat soft foods so insure "safe passage" as the intestines feel inflamed.
Grace, I understand what you are doing with the miralax. Have you been tested for celiacs? I was tested for that too in July and don't have it. Therefore there's no need to eat a gluten free diet. That said I buy gluten free pasta to cook with. I started doing so when my BFF, who has celiacs, came to visit and I thought the rice made pasta tasted the same so kept buying it. I think GF keeps it from slowing down my system as much as regular pasta. Do you ever feel like a big science experiment?
Just when I think I've got it about figured out something different happens. The premise of a j-pouch sounds simple and it's far from it.