I totally agree with Nanners, this type of pain is "classic" obstruction pain. Both times I had an obstruction I had this pain like contractions, and yes, I did have gas and went to the toilet. Went both times to the ER, and found out that these were partial obstructions (that's why I still had gas and bms), but still, there were obstructions which is not fun at all. My advice is that if the doctor told you to have a CAT scan, you should do it. Obstructions are not something to mess around with, plus in the hospital you will find immediate relief.
Christina