Depends on what kind of catheter, but I assume you mean the standard Foley (urinary) catheter. Most likely what is causing this is obstruction of the fill lumen by salt that has crystallized out of normal saline. This happens when the balloon is filled with normal saline and not water. Are you able to fill and empty the catheter? If not then most likely it is clogged with salt. Remedy is go see a doctor, they will probably cut the catheter completely in two closer in the middle of the catheter to release the fluid in the balloon and then the catheter should come out.