What does dig mean in "You are dug into a position"?
The context is :
I think you are dug into a position. And you think it's a sign of weakness to change your mind.
"Dug in" refers to earthen field fortifications used in military conflict. The idea is that the person has "fortified their position" and is prepared to defend rather than abandon it. It implies that they're invested in the stance they've taken and lack flexibility to change (just as fortifications increase one's ability to defend a position, but rob one of mobility).