I recently had a Inguinal hernia repair 4 weeks ago (and a lot of scar tissue removed resulting from my aorta bi-fem bypass I had done one year ago). At about the end of the 2nd week, I will wake up in the middle of the night stretching. My abdomen will get real tight and be crunch up. My ab muscles seem to do it automatically. Also, as this is happening and I try and turn onto my side, I have excruciating pain. Once I am up and out of bed, this all goes away. Why is this happening?