Conquer UC,
It sounds like Hemmeroiids to me have you ever taken a mirror and looked down there. Hemmeroids will cause alot of rectal pressure, and it feels like your anus if throbbing because the viens are swollen, hemmeroids are definately NOT painless they hurt. BM's will be skinny or maybe nothing at all because the area is swollen making things difficult to pass. You will see blood streaking the BM or on the toilet paper.
t can also be proctitis causing an inflamed rectum, both can cause similar symptoms.
Either way rectal foam or suppositories with cortisone help to decrease inflammation.
Soaking your rear end in a hot bath with epsoms salts many times a day helps and it keeps the area clean.
Metamucil helps alot if its hemmeroids or proctitis. It bulks the stool making it easier to pass therefore your not straining, which will make things throb. Make sure your drinking lots of water.
Witch hazel on a cotton ball and stick it at the rectum and leave it there for a bit, helps with inflammation and pain.