How long should a catheter affect urination?

I had surgery on Wed during which they used a catheter on me. I know it can cause problems with urination afterward, but I was wondering for how long. I've been trying to drink a lot of fluids, including cranberry juice, but I'm still having a lot of trouble starting and keeping up a urine stream. It's also causing pains in my urethra, but not when I am urinating like with a bladder infection.