Dear Welcome to HCM We understand your concerns I went through your details. You said when i masturbate semen doesnt come in urine till one week after that it comes in urine . That is natural. Semen is produced whenever you are sexually excited. Produced semen is stored inside your body. Stored semen is a waste product now and body needs to throw it out if it is in excess. When you masturbate, naturally, the stored semen is removed. If you do not masturbate for long, body needs to throw the stored semen. Therefore body find its own way either through urine or through nocturnal emission. Nothing to worry. Burning sensation could be different issue. Burning happens because of inflammation or infection. Drink plenty of water. If burning persists, consult a doctor. If you require more of my help in this aspect, please use this URL. http://goo.gl/aYW2pR. Make sure that you include every minute details possible. Hope this answers your query. Available for further clarifications. Good luck. Take care.