Lower Back Side Pain More Condition_symptoms What Is Causing My Lower Right Side Back Pain?

What is causing my lower right side back pain? - lower back side pain more condition_symptoms

Since this morning I went to the pain in my lower back straight. Just above the waist. Then, when I went to the toilet to go after the application, it was a little blood. Then I went several times, and there was no blood. Who has an idea what could it be?