What Causes Black Coloured Stools Along With Abdominal Pain ?

i have left side stomick pain ...black stool it started after my blood test on monday,,at night i couldnt eat anything i couldnt sleep all night on monday.. after taking 2 advil i got some sleep..i had tomato soup yesterday and had soup today the pain wont go away. i have a kidney stone in my left kidney..lower back pains ,, unable to go out .. i been in bed sufring from the pain since monday..