How do I care for this knee injury?

I'm not completely sure what kind of injury it is (muscle, joint or something else), so I don't know if I should be using it, staying off it, cooling it or heating it. O_o
Last night I was practicing kick-boxing, but I'm still somewhat of a novice, and I wratched up my left knee. I'm not sure if it happened when I was kicking with that leg, or when I was twisting on it to kick with my other. I didn't notice anything till I stopped.
Now I get a real shooting pain (right near the kneecap, on the outside edge of it) when I stand on it straight (when you lock the knee), and when I bike or use stairs it kind of grinds or clicks. O_o It is only a bit swollen and warm, on the outside side of the kneecap, and also when I walk it feels like there's a pillow in my knee.
I was going to go running tonight - is it still ok to do so? Running on it doesn't seem to hurt it.
So, any advice?? Does anyone know exactly what I did to my knee? Thanks!!

Oh, I should mention that it doesn't actually hurt unless I lock it, or put to much weight on it while it's bent (ie: stairs).
It feels weird when I walk and bike, but doesn't hurt.

Sounds like a minor sprain to me. Just stay off it until the swelling goes down.

Worse case scenerio, it's a torn Meniscus.

Symptoms of a torn meniscus are particularly pain, swelling, catching and locking.

A torn meniscus usually produces well localized pain in the knee. The pain often is worse during twisting or squatting motions. Unless the torn meniscus has locked the knee, many people with a torn meniscus can walk, stand, sit, and sleep without pain. Other people find that the torn meniscus prevents them from participating comfortably in their usual daily activities. But I'm no doctor, so if conditions get worse in the next couple of days, set up an appointment.

probably not a good idea to run on it. maybe use the RICE method: rest, ice, compression, elevation. or see your doctor.

If it is swollen then it is inflamed, prob a tendon. RICE it -rest ice compression elevation. ice 20 on 20 off. gets worse see dr

Ok you obviously have some swelling and until this goes down anything you do will make it flame back up. Especially running. SO chill out try putting Heat to loosen it up and COLD to bring down the swelling. If it bothers you a lot get some ANTI-INFLAMMATORY from yur doc.

You might have strained your collateral ligaments. This happens when your leg is 'twisted' when you were kick-boxing. Happens also when you suddenly change direction when running. Won't recommend running. Give it a little rest until the swelling settles down.

I'm not a dr, but I have knee problems.

That clicking/griniding may be indicative of a more serious problem (like a cartilage tear)

Other than R.I.C.E, and taking NSAIDS (Advil, Motrin, e.g), I would see an orthopedic specialist ASAP if the pain or swelling persists, if you find your leg buckling or if you cannot walk.

I think it sounds like you might have torn your meniscus cartilidge. You need to go see a doctor. If this problem is not taken care of, it can cause some long term problems....it usually presents itself as a clicking or grinding sound in your knee, can be caused by repetitive use of the knee, and can be sharp pain It can be that you can't bend it all the way or straighten it the whole way. Most of the time it can be easily taken care of.

Good luck!