I had a DIEP surgery in January 2013. The recovery was good. But I feel this piercing pain on the left side of my lower abdomen every time when I do exercise like sit ups. Regular exercise like running or other kinds of muscle training doesn't cause any pain. I did sonography during the summer and the doctor said he can't see anything wrong on the image. Is this pain normal? What can possibly cause the pain? Is there any way to find out what happened and remove the pain?