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At your age apart from fibromyalgia multiple joint pain is seen in hypothyroidism, low Vitamin D levels, Low Vit B12 levels, anemia, Hasimotos 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.
Please talk to your doctor regarding these and get yourself examined accordingly. Once the problem is caught and treated, the pain will go away. Take care!