Does masturbation causes knee pain if not what is its side effects and how can it is controlled what food you doctors suggest?
Masturbation. Maybe it depends on what position you're using to masturbate. For example being on your knees on a hard floor could result in knee pain. Otherwise there would be no relation. "side effects" would be release of pent-up sexual tension, rather than anything harmful. Unless you're doing it compulsively many times a day or in public places, it is a safe activity that can be enjoyed ad lib.