Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. According to history provided you are having left sided lower abdominal pain and also positive history for ulcerative colitis so inflammatory bowel disease or diverticulitis like presentation can be there. If frequent urination history is present then USG pelvis scan will be beneficial for that and diabetes also should be ruled out. Take more fibre diet and green leafy vegetables more. If blood in stool, diarrhea, fever like complaint present then mention about it and provide your reports for giving further comment. Consult physician for examination. Hope I have answered your query. Let me know if I can assist you further.