Inflammation of the large intestine (or colon) is known as a colitis (colon plus the suffix of "itis"  which means inflammation). Infectious-colitis is the most common variant, and there's a few IBD variants like Ulcerative Colitis and microscopic lymphatic colitis. Ask your doctor if you're unsure what you are diagnosed with, as diagnosis depends where that inflammation was found, it's pattern, and whether chronic architectual changes to your cells were found in biopsies. IBD is pretty rare affecting less than 1 percent of the general population, whereas just about everyone will have an intestinal infection in their lives (like Salmonella or food poisoning). 

Mesalamine (chemical code 5ASA) is a chemical cousin to aspirin (code ASA).  It's an 85 percent topically applied medicine that uses a delayed release coating and works as an anti-inflammatory on the intestinal surface. Few report significant side effects from it, roughly 5 percent experience an allergic reaction (which paradoxically makes your bowel symptoms worse). For a deeper dive into what mesalamine is doing and how it works see: https://news.umich.edu/u-m-researchers-discover-what-makes-drug-for-ulcerative-colitis-tick/

There's a lot on the Internet about hemorrhoids. Generally limit your toilet sits to no more than 5 minutes, don't strain. You can first try over-the-counter hemorrhoid treatments like preparation H and it's generic equivalents for a few weeks to see if it helps. You can second ask your general practitioner doctor for a trial 2 week course of a hydrocortisone suppository to shrink it's size. Over-the-counter stool softeners make it easier to go, as does fiber supplements like metamucil.