The purple discoloration of your knees with exercise might not be related to the underlying pain. I say this because, when people exercise vigorously, sometimes the skin changes colors due to sweating and changes in blood flow and this should not in and of itself cause pain.
However, the persistent pain in your knees definitely needs a more complete evaluation. If you have already seen your pediatrician
, it might be time to get an opinion from a sports medicine doctor
or an orthopedic doctor. It is possible that your scoliosis
and your knee pain are related, as postural problems from the scoliosis, if it is severe, may cause mechanical imbalance that puts excess pressure on your knees. However, since you are very physically active, it is also possible that there is something going on in your knees themselves. One common knee condition in your age group is something called Osgood Schlatter disease, although other conditions, including "Runner's Knee," are also very common. A sports medicine or orthopedic doctor should be able to perform a thorough examination and help you figure out what is going on. They may prescribe physical therapy or specialized exercises to help you start feeling better!