Had Rectal Bleeding. Have Abdominal Pain. Get Diarrhea. Bowel Movement Is Not Stable. CT Scan Shows Lesion In Liver. Blood Test Is Normal.

Hi, last week I had rectal bleeding. For quite some time now I have been experiencing abdominal pain. I get diarhea every now and again. My bowel movement is not stable, sometimes I could not poop for a week and when I do, I have thin poop. I am often tired and get woken up by abdominal pain at night. I saw an after hours doctor about the rectal bleeding and after examination, she told me my lower left abdomen felt tender and was advised to see my local GP. I consulted my local GP and sent me off for an abdominal ct scan for colitis and blood test...my ct scan result came back and my GP told me result was okey but has found a lesion in my liver. So I was referred for liver ultrasound. I had the ultrasound today and the technician was not able to locate this lesion so the Radiologist came and after thorough check, she found the lesion and she said she could not clearly identify the type of lesion and that she has to think about it if further test is required to assessing this lesion. My blood test result also came back okay except the amylase was higher than normal. My GP could not tell me what is causing the abdominal pain and the bleeding I had. My GP said he will refer me for colonoscopy. If ct scan is not showing anything, what good is colonoscopy do me?