Wondering if something else is going on

I was diagnosed with signet ring cell carcinoma of the right side of my colon...from terminal ileum thru to cecum. However, I have a lot of pain in my upper abdomen. This pain is what first brought me to see a doctor in June. I was told it could be an ulcer and told to take Prilosec. Months later, I find I have colon cancer, mostly because I stopped pooping and was afraid I had appendicitis. However, the pain has never gone away from my upper abdomen. Sometimes the spasms are so bad, I want to go to the emergency room. The doctors say it could be referred pain from my tumor, which has caused a blockage. I’ve been untreated since the cancer was discovered and am awaiting a right hemicolorectomy (or however you spell that). I’ve had an upper endoscopy and no cancer was found in there. I want to be sure we’ve checked all possibilities for other cancer since I have pain daily. I just don’t buy that it is referred pain. Because I feel the spasms (not unlike labor pains) and feel gurgling directly in this area...my stomach or around there. Any suggestions into further investigations before I proceed with the surgery? I’d appreciate any thoughts, suggestions, etc. I know sometimes we have to be our own advocates with this. Thank you, leslye