I started having diarrhea a week ago, and it was not getting better. Yesterday morning I started having cramps, which worsened as the day continued. The stomach pain was severe, and I could not get up. I went to the hospital, and they did blood tests, and my white blood count was up. He told me that it was an ulcer, gave me medications to coat my stomach, and gave me an antibiotic. My stomach feels better, but now I have pain in my muscles like they are bruised; it is worse on the left side of my back. Why?