Severe Knee Pain In Both Knees.?

I'm 14 and my knees ALWAYS hurt. When I squat or kneel, my knees pop really loud, and I can't sit crisscross apple-sauce for more than 3-4 minutes without a really bad pain in my knees! I also have trouble climbing up and down stairs, and running/standing for long periods of time. They have been hurting for about 11 months now, and I don't know what's wrong. No swelling, just severe pain! My dad has bad knees, and he has had to get surgery three times, but I don't know why. Could it be genes from my dad, or something else? Do I need to see a doctor? Should I wear a brace? PLEASE HELP ME!