What Causes Pain In Left Side Rib Cage?

The last few days I felt serious pain on the left side under the rib cage. The pain is severe when I cough or sneeze or even if I have to scream something or for someone. I have not been able to sleep on my left side due to the pain. It's difficult to get in and out of the car. I do seem to have gas in my body. I am not vomiting, nor have a dierhia