Emma`s comment is correct. Your contact was no risk. Your symptoms may be all prostate. You may consider a visit to a urologist for a prostate exam. Take care
How many types of STD test are there and how are they carried out?
How long would it take to know the STD test result?
Can I be infected with yeast at prostate instead?
"Subtle pain" especially without discharge is not a symptom of an STD. It could be your anxiety from this event magnifying normal sensations in your body. To ease your mind, you could be tested for STDs (if you haven't already).
You can have an STD that remains asymptomatic, but the only way to know is to be tested.
My guess is that this is not STD-related. But if the pain continues, see your doctor to rule out any other medical conditions.
Good luck,
Em