What Causes Pain In Left And Middle Abdomen?

I have abdominal pain, it started on my left side as a sharp burning pain and now has spread to major discomfort across the middle abdomen. Makes it hard to sit forward and move around. It has been 5 days . I went to emergency, they did blood work and urine work . Nothing really showed there. I had small amount of blood in urine but Doc didnt think it was anything. He sent me for an ultra sound for pelvis and abdomen. that was 2 days ago and I have heard nothing but pain is getting worse