When i defecate, i have a lingering burning sensation as if i still have additional waste.?

Many possibilities: Constipation (or just incomplete emptying which is essentially constipation), hemorrhoids (very common), parasite/worms (less likely), rectal prolapse (rectum trying to exit via the anus). Don't strain or grunt, eat lots of fiber, drink lots of water and have your doctor evaluate this.

Maybe anal fissure: Pain or burning sensation assoc. W/ bms can be associated with an anal fissure. Typically located posteriorly at the end of the anal canal, they are not easily seen on colonoscopy & even direct visualization can be difficult. Increase fiber & bulk laxatives and topical Diltiazem 2% ointment can help. Can require surgery. A colorectal surgeon can help. Fascrs.Org/patients/conditions/anal_fissure.