Do I need dialation?

Dilation can help with strictures, but strictures aren't the only things that can make it hard to empty a pouch. I think you need a proper pouch exam by a knowledgeable gastroenterologist, or perhaps your pouch surgeon.

It sounds like you need to see your GI or surgeon.  When my stricture problems began it felt like what you are describing.  I have a bidet and found that shooting some water up like a mini enema was what I needed to do.  It progressed to needing these mini enemas 5+ times a day.  When I had to be away from home I had to give myself enemas where I was staying. I think my situation was hopefully worse than yours.  I was dilated during several pouchoscopies and then under anesthesia before my pouch was finally declared as dysfunctional.  I also had other chronic problems.  I was on a mainly soft/liquid diet for 8 months before then too.  So your prune juice makes sense to me.  There are many on here that dilate themselves or need it done annually during a scope and so on. The sooner you get to a doctor the better things should be for you.