Hello, 6:30 am this morning I flew from Richmond, Va, to Dulles, Va. That flight took approx 1 hr. Then my flight from Dulles airport to Pittsburgh took approx an hour. Once I checked in my hotel room, I noticed that my right knee started throbbing. So I elevated it and tooks some motrin. The throbbing is intermittent. I am 52yo and wondering if this is something serious? Pls help me....