Hi, and thanks for your medical question on eHealth forum!
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.
All can increase the WBC count. Most of these will also cause tiredness and fatigue. You should consult a rheumatologist for this. Hope this helps. Take care!