Referred Pain
Sometimes thigh pain does not come from a problem in your legs. It is sometimes referred pain, which means pain from another part of your body that is felt in your legs by mistake.
For example, sometimes you can feel pain in your thighs when the real problem is located in your thighs or knees. Since the articulations are very near the area and pain in these tissues is received by the same nerves, sometimes the signals become crossed, and the brain misinterprets pain.
Another example of referred pain is kidney stones. When kidney stones run down your urethra, the pain can be felt in your groin, testicles, and sometimes your thighs. In such cases, the musculoskeletal tissue of your legs is probably intact, but the pain can be very severe.