It dosent hurt when im running, or even walking around, but if i have to keep my knees bent at the same angle for a long time, it hurts, has anyone experienced this, what did you do about it.

I'm guessing bad circulation, you know how sometimes your foot tingles if you don't move it? Well ya since your keeping your foot bent for a long time I guess your blood isn't circulating, still this isn't normal (it can happen in older people) and can be very serious.

You shouldn't be on the forums right now I suggest calling a clinic and telling them about your knee, if they ask you to come in then you should.

Sounds like you have restless leg syndrome Zeus.  But I think I might know what you are talking about, my patellar tendon aches pretty badly when I sit with my legs bent for a while, especially after a hard workout.  I think I have a patellar tendon strain, and you might too if its the tendon right below the kneecap that hurts.