This is Dr. David
how long has this been going on?
burning of your urethra can be from a bladder infection
or urethritis or passing a small bladder or kidney stone.
burning of the anal passage can be from eating spicy foods or from colitis or from anal fissures or hemorrhoids.
do you have a doctor who can check your urine for bladder infections?
do you have a history of hemorrhoids?
have you eaten spicy foods recently?
have you been sexually active recently without protection?
are you having any penile discharge?
condom would have protected you against HIV and bacterial STDs.
that is good no discharge.
I would get your urine checked for possible urinary tract infection
anal passage would be something else
like an inflamed hemorrhoid
or anal fissure
STDs don't tend to cause inflamed anal passage.
I don't think they are linked.
there are many types of STDs.
and different STDs cause different symptoms
usually for men penile discharge and burning
not anal burning.
do you have excessive anxiety before?
or panic attacks?
excessive anxiety can cause nervous bladder symptoms and make you feel like you have burning down there if you are worried about an STD.
do you have a history of excessive anxiety symptoms?
you should talk to your doctor about it.