Muscle At Left Side By Waist What Is This Pain In The Left Side Of My Waist?

What is this pain in the left side of my waist? - muscle at left side by waist

For over a year ago I had an annoying pain in my left side ... Size. I believe that if I sit upright. It bothers me when the drive sit for an extended period and at work. I have a sedentary job, so I sit all day. In thought he might have pulled a muscle. I went to the doctor when I had problems with, but all what was expected, Tylenol. Do not think the doctor cared not know too much, or what was the problem. I do not feel discormfort go to bed or stand. Has anyone suggestions on what might be? Thank you.