Hi everyone, was just looking for a bit of advice, not sure whether to push for more tests but don't want to waste anyone's time

Coming up for nearly 12months I have been experiencing very painful cramping during the night in my upper left abdomen,near the central stomache area and just to the left under my left bottom rib. The pain is severe when it comes and will wake me up, and keep me awake. It's too painful to lie on my right side and although I can still feel it if I lie on my left sides it eases slightly. 

I had a CT scan which I believe was chest & abdomen and all looked ok.

Pain has continued, I've just put it down to muscular pain..

But for the last 3 to 4 weeks I've had co tinuous loose bowels which isn't normal  for me and lower back pain.

Does this sound anything like bowel cancer has anyone had similar symptoms and should I push for more answers? Also could a CT scan have missed anything??

Just after some advice! Thanks so much x