Well, oxycodone and morphine are unlikely to be the cause of pain. I am not sure what genetic condition you have, but if it is causing knee pain, it can also cause shoulder and elbow pain. Multiple joint pain is seen in fibromyalgia, hypothyroidism, low Vitamin D levels, Low Vit B12 levels, anemia, Hashimotos thyroiditis, gout (can sometimes cause multiple joint pain), rheumatoid arthritis, osteoarthritis, SLE, electrolyte disturbance particularly those involving calcium and magnesium, parathyroid gland problems, chondrocalcinosis and chronic fatigue syndrome. In females, menopause or menopause like condition caused by PCOD is often associated with Vit D, calcium and hormonal disturbances and this causes multiple joint pain. Please talk to your doctor regarding these and get yourself examined accordingly. Take care!