6 mos ago i got diagnosed with 12 degree scoliosis and i can feel its progressing and moderate knee and shoulder pain? could it be from my scoliosis?

Knee and shoulder : No knee and shoulder pain is not related to scoliosis unless a nerve is entrapped. This should be investigated.

Scoliosis : Is diagnosed when the curve is over 10 degrees typically on two visits 6 months apart. 12 degree curves can vary from 6 to 15 degrees based on measurement error. If you are 18 and your curve is only 12 degrees the chance of your curve progressing is near 0%. Shoulder and knee pain typically are not related to mild or marginal scoliosis. Small curves can just be a result of a shorter leg too.