I can't speak for your specific scenario of course, but your jpouch probally is connected, it's just not in use. In the UK at least they usually connect you all up, the pull the higher digestive tract out through your belly, snip a hole and call it an ostomy. The bit after the ostomy is then sewn shut to give the pouch time to heal without use.
My doc told me time and time again I wasn't connected, but 100 percent i was because when I drank beetroot juice or something I got some coloured discharge.
So to point 2, even though your pouch isn't connected, and even assuming it's sealed below the ostomy 100 percent, the lining of the pouch is healing living tissue! As it regenerates the dead cells fall out and have to go somewhere so you get discharge. As your inflamed in there, you probally have some stuff that needs to come out but won't come out easy. In hospital I (and am sure others) had a rectal drain sewn in for place for this reason. This proper hurt for me..
Point 3, you don't say how long you are out of surgery for, but I couldn't sit up for 3 weeks.. I would either walk (hunched) or lie in bed with a slight incline... Anything else was too painful
Try bathing your butt with warm water and see what happens.. it would help the sphincter relax and make it easier to pass discharge.
If that doesn't help, and if the pain is significant and persistent is worth mentioning to a doc