I am sorry to hear about your pain. First off, having black stools is very worrisome as this commonly is referred to as melena, or bloody stool ( digested blood from your upper Gi tract causes your stool to become black in color). If this is persistent you need to see your primary care physician immediately for further evaluation. Now i also see you recently had some type of abdominal infection, hopefully you completed your antibiotics for this and have followed up with the prescribing physician. In regards to pain in the lower abdomen and into the testicle following any lower abdominal surgery, the a common cause is ilioinguinal or genitofemoral neuralgia ( nerve pain). Another possible cause would be a inguinal hernia, which can develop from straining. I would recommend seeing your primary care for a careful physical exam to help differentiate between these two possible causes. I hope you feel better soon.