What Causes Severe Pain In Lower Right Of The Abdomen?

Hi. I have been having pain in my lower abdomen for the past few days. My entire body started aching today, and I have been experiencing pain in my right lower side when I cough. I have also been nauseous and unable to eat anything for the past two days. I went to a doctor at a walk-in clinic, about a week ago, because I was having burning with urination and increased discharge. The doctor checked for a uti, and other stds because they said I had lesions. Treated for herpes, but all of the tests came back negative, including the hsv swab. My pcp said there was no sign of lesions or a uti. Do you have any idea what this could be?