This could really be anxiety and guilt, too. Anxiety can give you real physical symptoms, and since you say you have "slight" pain, and a "general soreness", it sounds more like anxiety.
It could also be a UTI, and the timing is purely coincidental.
Really, the only thing I'd be concerned about is NGU, which is an infection in the urethra that can be caused by normal mouth bacteria. They should be able to tell from your urine sample, but make sure to ask if they found any white blood cells in it.
Hi contracting any std from oral sex is very low risk and testing would not be recommended unless you get a white puss penis discharge or genital sores about a week or 2 later. OR if you have a long term partner. Any risk no matter how low would be considered a risk to your partner. Your pain is most likly an injury from the act itself.