Dealing with same pain, left side, under left breast area and slightly above belly button. The first bout of this pain lasted months. Lying on my left side was uncomfortable . Also had ct scan which was normal. My GI suggested both colonoscopy and upper endoscopy which I have put off. I am 68 and am getting increasing leery of colonoscopies at my age of 68, especially while having this on and off pain which I likened to a diverticulitis pain. GI suggested that I had incomplete bowel evacuation, which I have had since my cholecystectomy 17 years ago. My stools are very soft or worse according to how much fat I might consume that day and can be sludge-like which is so frustrating. I also have some internal hemorrhoids which have triggered some tenesmus. He suggested a powder fiber supplement and drinking 62 oz of water per day. This had helped with the pain for several months; was having more formed and complete bowel movement. Pain is back again despite this regimen however and my side hurt again last night while lying on it and laughing. I feel your pain and frustration ...no pun intended . Good luck. Hope you will report after your colonoscopy.