Knee Problems.?

I just turned 13 in February. One day about 6-8 weeks ago, I was running home from a friends house halfway down the street because I did not want to be late. After running for a little while, my knee started hurting. So, I started walking. After a while, I ran again. Then it hurt after about 30 seconds, so I walked again. I tried to run again, but it hurt right away, so I just walked the rest of the way home.

I forgot about that day until 3-4 weeks later when my knee started cracking and hurting worse than when I was running.

The other day, it locked up for 12+ hours. The next day I woke up, and everyone in the house heard it crack.

My questions are:
1. What is wrong with it?
2. How can I care for it?
3. If something is horribly wrong with my knee, why was there about a month-long "break" of it not hurting between the possible injury and when its cracking and locking up?
4. Have you had this happen?
5. Are you a doctor or nurse or in a Medical profession?

you guys are not helping! i am going to go to the doctor, but first, I would like a vague idea of what's going on. please and ty.

You should go to the Doctor asap. There is a cartilage between the joint of you knee, which is the largest joint you have. It sounds, like that cartilage is damaged. Today, a small incision and short operation can take care of that. But don't drag it out, it can get only worse.
For the rest of your live, do some specific exercises (10 minutes a day) to strenghten the muslces, surporting your knee. That and no sports, where you twist and turn, will prevent future headaches.
I would go to at least two differnt Doc's to get differnt opinions, they are all only humans.
(My both knees are done with, because I didn't listen)

sweetie go to the doctors..

Here's a wild idea: GO TO THE DOCTOR

go to the doctors

see a doctor

1. only way to find out whats wrong with it is having it checked by a doctor and having xrays

2. until you see a doctor a good thing to do is keep it elevated on a pillow and ice it for 20 mins then take the ice off for 20 mins and keep repeating.

3. you probably have felt a break of having no pain because you have been favoring the knee by not running or over exercising the knee

4. I've had patients with similar problems and usually its been things like arthritis or older people that need knee replacements

5. I work at a hospital, I'm a nurses aide

Most likely b/c of your age you have patellofemoral syndrome. It is treated with physical therapy. You will work on the strength of your hip and butt muscles b/c they are usually very weak in kids your age. If you would like more info then feel free to message me