idk what to do

I'm 16 and I've had this pain in my knee for about 4 years now. I went to my family doctor last April and all she did was tell me to do some stretches. I did them and it worked for the pain I was having then but the pain is different and worse now. My mom keeps saying she'll make another appointment but she hasn't yet and neither of us know if the doctor will even be of any help.