I have very similar thing. It scares me because I've developed gastritis recently and I wonder if it's related. Do you still have it?
When I'm lying down my lower belly pulls in and the area on the lower right sticks out more than on the left. Sometimes it's tender when I push on it, sometimes not. Sometimes it gets much smaller but then reappears later.
It makes me nervous but I am even more nervous to go to the doctor.
I vote for hernia, even tho it's not painful. You should see your regular doc and ask him to refer you to a surgeon who can put everything back together for you. The reason I concluded hernia is because you said you felt a pop when sneezing, lifting, and ab workout. That's precisely what causes a hernia, any of the three, the abdominal muscles rip away and the insides will bulge out in that spot.