Reason For Painful Erection?
Erections are usual at this age,but if it is painful then something could be wrong.
You are describing something that is called priapism. It is medical condition, in which the penis is frequently erected and painful. It is caused by increased blood flow and the exact cause isnt known yet. It can occur without any cause or in some haematological and neurological disorders.
Well i dont know for how long his erections last, if it is longer the 4 hours then you should visit doctor. If his penis becomes swollen and inflammated then go to ER.
He can help himself if he start exercise after he get ercetion ,he can run or do pushups,or walk up stairs so that blood goes away from penis.
If he has urinating problems he should also visit urologist.
Second, painful erections can be caused by phimosis and preputial adhesions so if there is anything strange about his penis or testicles such as color or morphology you need to seek for help.
Hope I ve been helpful, If you have any question I am here