Pain and very strange feeling pain behind knee

[W2510]

Im 15 years old and in pretty good health, about 2 weeks ago I was ill and as a result was bedridden for a few days. When I recovered I noticed moderate pain in my leg when walking and bending it. The pain was as if i had overworked it and not stretched. A few days ago I decided to try some stretches and weights with it. The pain after doing so is now about 10 times worse. I can barely bend my leg and there is a weird feeling when bending as if there is water there. decided to ask here as everyone i have asked/complained to has just said the usual, rest it and it will be fine in a few days.There is no visible swelling. It has been getting worse and now when I sit down my foot goes slightly numb.

I might be overreacting but would like some advice on what to do :D

Ps: I have had a dislocated shoulder before and the pain is about the same when I try to bend the leg fully back.

[specialmom]

At 15, the best thing to do is to tell a parent about this.  They are best to guide you.  Pain behind a knew is often due to inflammation which ibuprofen can help, sometimes it is from tight hips.  Stretching may help.  I would try ibuprofen with your parent's approval and stretching and actually staying off of it is not great---  keep it moving so it doesn't get stiff.  good luck