Some times after I masturbate I get a cramp in my anus
Reasons Behind Pain after Bowel Movement
Proctalgia fugax , a variant of levator ani syndrome , is a severe, episodic pain in the regions of the rectum and anus. It most often occurs in the middle of the night  and lasts from seconds to minutes;  pain and aching lasting twenty minutes or longer would likely be diagnosed instead as levator ani syndrome. In a study published in involving patients, the attacks occurred in the daytime 33 per cent as well as at night 33 per cent and the average number of attacks was Onset can be in childhood; however, in multiple studies the average age of onset was
Prostatitis is very common with half of all men experiencing it at some time in their life. It accounts for as many as 25 per cent of all visits to the doctor for problems in the genital and urinary systems by the young and middle aged. Prostatitis is the name given to inflammatory conditions of the prostate gland. It can be very painful during urination or ejaculation and you need to see your doctor to ascertain the cause and get appropriate treatment.
Pain in the rectum is a common experience and is not, in general, due to a serious medical condition. However, the pain can be intense and worrying. It is usually caused as a result of straining and stretching the rectum when passing a hard stool. Anal fissures can also occur if the anal sphincter the muscle that controls the anal opening is too tight to pass stools. The pain is a sharp knifelike pain that returns during the times when the anal opening is irritated.