Right side back pain after ejaculation may be related to too frequent sex, inflammation of the reproductive system and organic lesions of the reproductive system. 1. Too frequent sexual life: If sexual life is too frequent, frequent ejaculation may cause overstrain, and after ejaculation, you will feel the right side of the back pain. 2. Inflammation of the reproductive system: Inflammation of the reproductive system, including prostatitis and seminal vesiculitis, because of the infiltration of inflammatory cells, can lead to pain when the patient ejaculates, pulling the right lumbar muscle pain; to be after ejaculation the passion fades away, the feeling of lumbar pain will become obvious. 3. Organic lesions of the reproductive system: prostate cancer, prostate hyperplasia, ejaculatory duct stenosis and other organic lesions of the reproductive system can cause ejaculatory dysfunction, pain and other clinical manifestations, in the process of ejaculation or after ejaculation, the pain radiates to the right side of the lower back, which will involve back pain. There are other diseases that can cause right side back pain after ejaculation, such as right kidney disease, lumbar muscle strain and so on. It is recommended that patients go to the hospital in time for examination and receive treatment after clarifying the cause of the disease to avoid adverse consequences.