Swollen pain in the left side of my stomach what is it ?

what i believe to be my large intestant or where it is located is a tube or cord ranging from the left side of my stomach near my ribs down to lower then my belly button becomes on and off swollen, sometimes bearing occasional pain in the general area, from some research i think it might be gas bubbles or maybe something to do with the birth control i started a few months ago. Its nothing that can be seen but i can feel it with my hand pressing in. it feels like it has little ridges or something, any ideas?