Ivd been having this left-sided pain, towards ribs/upper left/bottom left back that comes and goes. if i'm in certain positions i feel it more. this have been going on for a year on and off. can this be cancer? had colonoscopy 3 years ago?

To find cause you need a good physical and possibly some testing -before thinking of cancer. Good luck

Persistent pain in any part of the body can be due to many different causes(including, on rare occasions, due to Cancer). You will need to see a physician who can monitor your health and do the necessary tests in order to find the cause. I would be more concerned if the pain is increasing in intensity or has other associated symptoms such as fever , poor appetite or weight loss..