What Causes Stomach Pain And Blackish Loose Stools?

Hi... I appreciate giving me time to ask you about my problems. I had sudden stomach pains since December 2013. It went for long time. I went to different visit to my gp and been told its Acid Reflux...i took medications which didnt help. Then September 2014..i had a sudden pain on my lower right abdominal which has been removed immediately as it was appendix. After my surgery my stomach pains gone very bad. Sometimes i was crying out of pain. I been told its Gastric pain..i took so many different treatmenrs no help honestly. Then November 2014 my bowel habits changed and till today its gone worae...i go to toilet 5/6times a day honestly...my stool is different...sometimes...black dark..loose stool. .brown stool. I have seen no Blood at all. I havent lost any weight at all. But if i eat little bit like a bread or biscuit...i will go toilet within 30mins. Please help me. I took also IBS tablets...no success