The cause for your pain could be abdominal wall muscle strain, or a pulled abdominal muscle, when the muscle is stretched too far.
Symptoms are localized pain and discomfort with normal activities like walking.
Another problem that can develop years after appendectomy at the incisional site is incisional hernia.
Sometimes, before the hernia bulge is visible, the pain can be experienced as an early symptom.
In rare cases, people who have undergone an appendectomy can experience “stump appendicitis,” inflammation of the tiny part of the appendix that remains after surgery, many years after appendectomy.
However, lower abdominal pain that gets worse with walking warrants medical attention.
Best wishes!
Marija