I have two SCS's and also have had GI issues for some time. For me, I don't think they are related. I have changed my diet as I think as I'm aging that I don't digest food as well or as fast, and it has made a huge difference. Have had to stop eating high fiber foods and eat smaller meals and chew, chew, chew to make sure is easily digestible. I had been dealing with a lot of nausea, lack of appetite, easily constipated and feeling really bloated most of the time. Couldn't figure out why as I'm not a big eater.
GI dr. said it's Irritable Bowel Syndrome, which it may be, given the stress we are all under when dealing with pain issues. All I know is that changing my diet, drinking much more water and staying away from certain foods has helped a lot. Plus I've lost almost 20 pounds! So, for me, it's a matter of what I'm putting in my mouth and the stress that's affecting my GI track. Just my two cents (make that three, what with inflation and all)