Epididymitis does not hurt but the thigh root is hot and numb, which may be caused by prolonged bad posture, infection, lumbar disc herniation, pyriformis syndrome and other reasons. 1. Prolonged bad posture: If you keep bad standing or sitting posture for a long time, it may lead to poor local blood circulation or compression of nerves, causing symptoms such as numbness and burning sensation in the thigh root. 2. Infection: when the immunity of the body decreases or the thigh root is traumatized, it may lead to infectious diseases in the thigh root, causing suppurative inflammation, cellulitis, lymphadenitis and so on, resulting in symptoms such as numbness, hot pain, redness and swelling of the thigh root. 3. Herniated lumbar intervertebral disc: If the lumbar intervertebral disc undergoes degenerative changes, it will easily lead to the compression of the protruding intervertebral disc to the nerve root, causing symptoms such as numbness, burning and pain in the thigh root. 4. Piriformis syndrome: when suffering from piriformis syndrome, if it is injured, local edema, congestion, inflammation, etc. may occur, leading to sciatic nerve compression, thigh root numbness, burning pain and other symptoms. It is recommended that patients go to the regular hospital in time, under the guidance of the doctor to clarify the cause of the disease and timely treatment.