Hi, as the Mom of a level ten gymnasts, I've heard all of this before. One thing to consider is simply that your level of activity is just hard on a body that is still growing. There is a syndrome called, (now I will butcher this, so if anyone knows better, jump in) Osgoods-slaughter, or something like that, which simply means that your tendons aren't growing as fast as you bones. Several people on our teams over the years have had this.
The cure, is time. That doesn't sound so nice when you are trying to workout, but it is the good news. Icing after every workout can help keep the inflammation down. You could try icing and that means every time, whether it hurts or not.
i'm 13 and had surgery about 4 1/2 months ago to repair damaged cartilage in my knee. it was arthroscopic surgery and i walked out of the hospital, i only had to use crutches because it got so swollen. my doctor went in and took out the cartilage, cleaned it up and performed microfracture to help new cartilage grow back. i could walk normally without a limp about a week and a half after surgery. my cartilage damage was severe and full recovery was about 3-4 months. i had the surgery the very end of september and started playing lacrosse again in january. the physical therapy helped alot. i do wear a brace to prevent further injury but my doctor says i dont have to wear it. it took alot to get back to where i was before the injury but it gets better eventually and the surgery is worth it.
hope this helps!