Usually the front area is draped, but quite honestly, the last few that I have had, I have been too high on the drugs to care.
Even if you did not have polyps, it is typical to take biopsies from the walls of the GI tract, to check for nonvisible abnormalities. Usually 6-12 are standard depending on what the diagnostician suspects. For example, I have ulcerative colitis. As it stays in good remission, the disease is rarely visible to the eye on scope; However, the biopsies demonstrate the long term effects/microscopic effects of inflammation of the gut, as well as early changes that may indicate cancer developing (always a worry with UC)
In addition, you have had a large, long tube, put into a part of the body, not intended to have that done. It will have some bleeding. If people get bleeding from mild cases of constipation, something like a scope will definitely produce some bleeding. But it should not be a great deal.
As far as pain, if there is inflammation (from whatever caused the positive occult test), passing the tube may cause some sharp pain. Also, ocasionally, the scope trying to pass around corners (descending colon to transverse or transverse to ascending colon) will cause some sharp pain. Hopefully, the diagnostician added some more drugs then. Since the area of initial UC disease started at the descending to transverse corner, I routinely get some sharp pain there. You also get "inflated" with a great deal of air, to open you up and pass the tube. That, to me, has always been quite uncomfortable.
Just like the irritation of throat that occurs from passing an ET tube, post op, people will have a few days of discomfort following a scope. If in doubt, call the diagnostician and report thesee issues.