What Causes Pain And Tenderness On Left Side Of Stomach?

a few weeks ago i noticed a bruise on my left side of my stomach. there was a small one on the right side also. i didnt worry much cuz i was working in a day care with often kicking toddlers. the bruises cleared and then a low grade pain started over a week or so ago. it is tender to touch and warm to touch. tonight i just took my temp and it is 99.2. do i need an emergency visit? the pain is mild but fairly constant