I had the same type of pain a few years ago! I went to my doctor who had me see a specialist who worked with our local pro basketball team. X-Rays, MRI's, revealed nothing out of the ordinary. Anyways, I spoke with a guy I work with and his suggestion , since he runs marathons and road bikes, was to wrap it real tight and resume my workouts. I did this for a few weeks and the pain and swelling went away! Now, I am not saying you need to do this but do go see your Doctor first and if all is OK, wrap it up and maybe, just maybe, the knee muscles and joints just needed to be conditioned. On a side note, I have logged in over 10000 miles running and biking since then and just completed 4 road bike centuries back to back! Good luck!