Pi$$ing after masturbation

I have been masturbating for a few years.

However for about a year i have been having a problem where for whatever reason after masturbation i will feel an overwhelming urge to urinate (it feels like i need to empty a bucket from my bladder) and i will sit down to the toilet and realese whatever amount of urine that is in my bladder but no matter how much there is the undieing urge to urinate still remains.

It doesnt happen very often and at times it will be worse than others but i am often reduced to begging god for mercy (i am not lieing i litterally have to do it its so bad) and it happens about 1-2 times every 2 months.

I also have a slight pain in my urethra just bellow the tip of my penis. This whole problem is very worrying.

Also i have found when larger amounts of semen are ejactulated the problem does not occur but when i have a large orgasm with not much semen coming out i get the problem. And somehow massaging the scrotum during masturbation also help relieve the problem significantly.

oh and i also forgot to note that the unbearable deasire to urinate will eventually calm down in an hour or so.

I would very much like to get some help on what exactly is wrong with me as it is very, very, very uncomfortable and would not like to have it as part of my life in the many years to come, thanks in advance.