Need Knee Help - Fast!

Heres the deal, a while ago my knees started acting up (right knee in particular), and so I took some time off to try and deal with it. Well at the time I couldnt really pin point the source of the pain, so I didnt know how to fix it. Fast forward to this afternoon, I go out to try and train, and my knees are really killing me.

The most acurrate description of the pain is along the inside and slightly below my kneecap, and it hurts the most in my right knee. It doesnt hurt at all when I accelerate, squat, or jump. However, it really hurts like a mother when I decellerate. For sprinting this wouldnt be much of a problem, but I play football and with practice starting on the 20th this is a serious issue for me.

Does anyone know what, if any, condition this is? And how do I go about treating it quickly? Should I get a knee brace or something like that?

Anyone’s help would be greatly appreciated!

doctor, take some time off from the track, stretch good, but most important is the first point, doctor !!!