American Idol” contestant Phillip Phillips‘ bum kidney will NOT end his run on the show — , he’s still determined to compete … even after undergoing an extremely painful medical procedure.

TMZ broke the story, Phillip — who has a long kidney stone history — was rushed to a medical facility last week, complaining of some nasty abdominal pain.

According to sources, Phillip underwent a procedure to install a ‘stent’ in his kidney — a kind of medical tube thing — to help alleviate a blockage caused by kidney stones.

Here’s the catch — stents are super painful … the kind of pain that makes it hard to compete on a nationally-televised singing competition.

But Phillip’s dad tells us, his kid wants to stay in the competition as long as possible — despite the excruciating pain caused by the stent … and won’t have it removed ’til his “Idol” run is done.

Kid really does have some serious stones.