Thigh pain consider muscle strain, lumbar disc herniation, osteomyelitis, calcium deficiency, femoral head necrosis and other causes. 1. Muscle strain: if strenuous exercise or sprain, it can cause thigh swelling, pain, and activity limitation. 2. Lumbar disc herniation: a herniated disc compressing the nerves can radiate to the thigh pain, with no obvious pressure points in the thigh area, radiating to the calf. 3. Osteomyelitis: manifested by pain, redness, swelling and fever in the thigh. 4. Calcium deficiency: when calcium deficiency can also cause thigh pain and leg cramps, timely calcium can relieve. 5. Necrosis of the femoral head: Necrosis of the femoral head can involve pain in the thigh and knee joints and limp. There are many reasons for thigh pain, if rest does not alleviate it, it is recommended to go to the hospital for examination and further treatment with a clear diagnosis.