Welcome to healthcare Magic!
The pain in the old operated area may be due to two three causes.
There can be local bands formed postoperative period at the site and they pull the gut when the stretching postures are made.
Second possibility is of a weak scar which may partially tearing or sometimes scars
may give pain when pressed.
Last but most serious concern is incarcerated hernia
, when gut herniates through the scar and suffers the blood supply and produces pain.
If ignored or long standing the gut may become gangrenous.
You should avoid strenuous works and lifting heavy objects and avoid to turn on the belly down.
You should also get evaluated by a local surgeon and if needed get investigated to rule out serious concerns.
I hope the advise would be informative and useful for you.