Colon disturbance

This part of mine has a more regular occuring twitchING as best described. 4-5 days between bathroom times is my norm. Have days mostly around the day b4 BM day where I can feel the waste just sitting in that area and it will burn & also twitch. It's twitching now & just had a recent bathroom visit.. my routine has just worked out that way and slowly, I do a lactulose drink & have to wait at least 8 hours to push it all out but plus side I don't need assistance...
Assuming best bet would be a colonoscopy & most likely any response here aye?!
Yet any ideas nurse? What could be happening there? I'm weary of it.

Colon disturbance