Hi welcome to the health care magic Your colonoscooy report was normal, hence no specific organic cause present.... It seems to be functional bowel problem... Excess stress, eating too fast, smoking, excess fatty food intake are some causes... Try to avoid stress if you are taking... Include fruits and green leafy vegetables more in your diet... If constipation remain main problem than fiber supplement can be prescribed... Yoga, meditation will be beneficial to get rid from stress... If you have alternate diarrhea and constipation presention than it can be specifically irritable bowel syndrome Take care Consult physician for examination with keeping all this in mind... Hope your concern solved