Hello, slloyd, The location of the pain and some changes in your bowel habits point to som problem with your large intestine or the colon. If you are over 40+ years of age I suspect you may have Diverticulosis or pockets on the colon wall. This is more common on the left side of the colon although can involve any part of the bowel. If one of these pockets get infected , then you can have significant pain, fever, chills and even bloody dirrhea. In many cases , this is associated with spasms and the symptoms are similar to IBS or irritable bowel syndrome with abdominal pain and constipation. If you have not had a screening colonoscopy, you should get one. At the minimum, you can get a Barium Enema to see if there are any problems. If you have any family members with history of colon cancer , then you should have the colonoscopy. Same thing is true if there are any signs of blood in the stool, weight loss or anemia. Have your stool tested for blood and also get a complete blood work. For constipation, you can take stool softeners that are readilily available in drug stores. A high fiber diet and adequate fluid intake is very important. There is also a polyethylene glycol solution which is safe to take. Follow the instructions on the label. (MiraLax) There are generic alternatives to this brand. I wish you the very best.