My knee has pain from the time I wake up until bedtime.It goes away the longer I walk on it.If I drive for 30 minutes,and then get out of the car,I limp for a couple minutes or so until it goes away.It looks a little swollen,but it hurts like heck at times.Sometimes it stops me right in my tracks.It started one day after i painted my deck.There was a lot of bending and kneeling going on that day.Its been hurting for a month or so now.
I've had a lot of knee pain in the past mainly from partial dislocation of both patellas (Knee caps). I would suggest that you see a physical therapist to just check that everything is ok with your muscles. Are you putting any ice on your knee? And are you using any supports of any kind? You can pick these up at any drug store.