Weird pain in my knee?

I danced too, ballet and this may be you are pushing your flexibility too hard, don't stretch to the point it is uncomfterble, you can not gain flexibility in a day it's something you have to work on.

You may have Osgood-Slaughters Disease.

I have it. I got it after I started gymnastics. I just stretch a little more and about 2 times a week I stretch it.

Osgood Slaughters disease is a very common problem in children. It is an inflammation of the bone at the growth plate about two inches below the kneecap, where the tendon attaches. You can often feel or see a lump right at the site. It usually affects children during early adolescence. It affects boys more than girls, and occurs more often in physically active children. It does not cause any permanent harm to the bone or the tendon, but can cause a lot of pain and discomfort.

The cause of Osgood Slaughters disease is not fully known, but is probably due to the rapid growth that occurs in early adolescence, combined with the forceful pull of the tendon on the bone with repeated bending and straightening of the leg. The problem goes away when the growth plate fuses. The way to manage it is to have the child take a break from sports that stress that tendon. Ice and/or Ibuprofen will also help with the pain. Sometimes with a short period of rest (four to six weeks), a child can resume the sport again without pain. Protective knee pads may be helpful if direct contact is a problem. Osgood Slaughters disease is not an infection and is not contagious to other children(familyeducation)

You may have stressed or pulled a tendon or a muscle. Keep stretching and if the pain continues maybe you should consult a doctor just to see if anything is physically wrong or if it's something you will just have to put up with.

u could have pulled muscles