Have you been diagnosed with Fibromyalgia or any other pain syndrome?? If so, what you are describing sounds just like one of the symptoms of FM...Irritable Bowel Syndrome! Like Lupus, IBS signs and symptoms can vary from person to person and can include stomach pain, bloating, cramping and alternating constipation and diarrhea. However, some patients suffer from all of the above symptoms (as I do).
Because irritable bowel syndrome doesn’t cause any changes in bowel tissue or cause inflammation like some other diseases of the intestine (e.g. Crohn’s Disease and ulcerative colitis) it has not been found to cause more serious diseases, such as colorectal cancer.
It might behoove you to discuss your symptoms with your doctor. Even though there is no special test for IBS, your doctor can perform tests that will preclude other problems, such as colitis. It is basically a process of elimination. These tests may include a colonoscopy, blood and stool sample tests, food intolerance tests and X-rays. They will also need a detailed history from you.
I do hope that you can begin to feel better soon. I know that the cramping & pain can be unbearable. Believe me...been there/done that .
Peace and Blessings