one of my friends told me about a disease where you can get fluid in your ankles and knees
I can think of one off the top of my head...are you pregnant?

All joking aside - it depends on what kind of pain you're having (achy, sharp, dull, burning), where in your ankle it's located, what EXACTLY you do that aggravates it, if anything makes it feel worse or better, if there's areas that are specifically tender to touch, etc. If you can't answer those questions, the doctor probably won't do any additional tests like an x-ray or imaging study and will just tell you to wear an ankle brace for support, elevate your legs above heart level at night if they're really swelling, and take an NSAID like Aleve or Motrin for the pain.