Knee and hip pain Accutane?

I am a high school male athlete and have been taking Zenatane for 40 days. I started at 50 mg but during my soccer games my knees hurt and it was hard to run. I went down to 40 mg after the first month but still have knee and sometimes hip pain when I sprint. My skin is looking a little better so I am encouraged by that. Can anyone share with me your experience with patients who have had the same issues? Do these symptoms go away after you stop treatment? Is there anything I can do to lessen the pain?