How is the muscle pain in the lower part of the left thigh?

Generally speaking, it may be strain of adductor femoris or saphenous nerve pain. First, check whether there are tender points in the lumbar spine. Besides, whether the skin is numb or allergic. Consider it lateral femoral cutaneous neuritis.

Suggestion: Vitamins B 1 and B 12 can be used. Pay attention to the weather changes in daily life and strengthen exercise. Take calcium supplements and vitamin D to enhance the absorption of calcium (under the guidance of a doctor). Control your diet and don't keep gaining weight.