Thanks for contacting healthcare magic. You have problem of string like stool that may be because of low fiber in diet .Burning sensation after bowel movement that may be because of hemorroid problem. Anal fissure may cause burning sensation . If this problem are long time than may be there is infection in intestine. Celic disease may ruled out. Irritable bowel syndrom may cause this type of symptoms. Consent a gastroenterologist for further diagnosis. Stool examination test helpful to check any Infection and blood present or not. Total blood cell count and barium x ray of gastrointestinal tract helpful for further diagnosis. I hope my guidance is helpful to you.. Take care. Thank you.