i didn't go see my doctor, but one of my college roommates is in his last year of medical school (specializing in sports medicine actually, he's worked with the Texas Tech football team), and another of my college roommates has been a physical therapist for the past 4 years so i talked with both of them and they didn't seem too concerned. they both recommended to keep it wrapped, put it on ice at least twice a day, and keep it elevated whenever possible (i.e. when i get home from work).
i do remember several years back having some issues with my right hip that caused some aching down the side of my leg, but never as far as the knee. i mentioned this to my PT friend and he suggested doing some stretches and exercises for my hips. turns out i think this is the root of the problem, not the knee itself.
after just my 2nd day of stretching and doing some exercises, the pain was nearly completely gone. my PT friend said he's seen this in athletes countless times already, and it usually is the result of a lack of flexibility and/or starting a new training regimen at too high of an intensity, both of which i'm guilty of. i'm working on my flexibility and doing slower-paced rides and every day it feels better than the day before. i just need to resist the urge to ride too hard too fast, so i took the batteries out of my bike's computer and just ride at a pace that feels comfortable and focus on keeping a high cadence. it's tough getting passed by everyone on the bike trail, but i'm just putting my pride aside so i can get back into shape and hopefully avoid having this issue again.