I have a erection every half hour lasting a half hour only stops for 5 min it's been going on for three months now. it does not hurt nor have i hit it?

See answer: If your erections are preceded by sexual thoughts and arousal an emotional disturbance causing obsessive thinking may be the cause and you need to seek counseling. If that isn't the case then the situation you describe is most unusual you need to see a urologist to determine the cause.

If you have constant: priapism (erection) and you are not taking any herbal supplements to achieve that, especially if it becomes inconvenient/ painful, and you are not having intercourse or masturbation every hour, then you need to see a physician /urologist. If you have obsessive thoughts about sex, then a psychologist who specializes in sexual dysfunction may be of help.