I have had a slight stinging sensation, just to the left of my clit, since last night. It came on rather suddenly and has left me rather uncomfortable. I have had unprotected sex. A month ago with someone whom i do not know medical history. But i have had unprotected sex 3 times since then with a partner i have had for 3 years. There are no bumps, white spots, itchyness, or even discomfort while peeing. Just the stinging sensation. I am worried about STDs, but hoping it is something easily treated such as a UTI or something of the nature.