This bulge may be due to incisional hernia
at the site of previous incision for Cesarean section(Which means that abdominal wall has weakened in that area and deeper tissue is bulging out of this weakness in this wall).
As due to curiosity you may be examining the bulge repeatedly hence feeling more discomfort.
The diagnosis can be easily made by clinical examination and ultra sound
I suggest you should consult you surgeon who has done cesarean section.
Dr Rajesh Kaushash