I have a habit of sitting cross legged. i am now experiencing pain in my knee and thigh on the right side. i never experiencing this pain on the left side. what could this be?

If crossing the left leg over the right leg is your habit and your pain is worse when getting up in the morning, you may have pyriformis syndrome, a from of sciatica but in this syndrome the sciatic nerve is only compressed and inflamed at the buttock area, not from the lower back.

If sitting cross legged, ( which is a respected feminine etiquette posture) - causes one to have sciatic/ knee pain, then it might be health-full to change posture to a none pain producing one. The Physical Therapist could help also.