Hi Megan,
It's good that your pouch gave you 4 years of service before giving you issues. I think that gives you a head start in keeping in front of big problems, but maybe not without a bump in the road.
Here's to hoping this bump in the road is small and such bumps are infrequent for you!
The cause of pain can be varied. The pouch itself could be irritated for various reasons, pretty much all of which involve discomfort. Narrowing strictures at the entrance or exit of the pouch can develop even after years. Mild inflammation in the pouch and anorectal region that was under the radar for years can cause arthritic and other problems to arise seemingly out of nowhere. The rectum itself holds many nerve endings, and can be a source of great pain. Surrounding tissues can make it appear that the pain is in your rectum when it is really not.
Those are off the top of my head, and I'm a neophyte compared to some of the folks here who have some serious research under their belts.
I've had pain that has been through a catalogue of completely plausible diagnoses which turned out to be dead ends. I don't blame the doctors. Like my GP said, Rheumatoid conditions can appear to deliberately screw with you and have outwitted the best doctors on the planet.
But, there is also a list equally large of people who had an issue come up, and knocked back down with finality by their doctors in short order. Cults have grown around some doctors who seem to be particularly adept at solving our myriad problems.
If you are straining, maybe your lower pouch is inflamed, making it harder to pass all its contents, and bacteria left behind is creating more irritated tissue. If that's the case, the VSL#3 will help displace the bad bacteria with good bacteria. It's like a gang war, and your good bacteria must hold more J-Pouch turf than the bad bacteria.
The good bacteria acts like a barrier, and if it is successful, your pouch will return to its former benign self.
