Narrow and Flat stool from past 2years.

Sept 2017-started with IBS (frequent bowel movements (loose and semi liquid) especially after eating, Lactose and Gluten intolerance and problem in eating grains). Undigested food in stool very often. Lost 12kg weight in 2years. Occurence of hemorrhoids. Took some ayurvedic medicines and stopped taking lactose and gluten. Now from last 6 months again started taking lactose and gluten. Problems as on date- flat and narrow stool. Sometimes the stool becomes very narrow like wire. Sometimes can see grooves and ridges in stool .Can see a pinch of red blood sometimes in 15days in stool. Weight gained almost 10kg in last 6months. Very healthy with hb level very good. Lower back pain is an issue. Pls suggest what can be issue. I am 37 years healthy person.