Chance of having an STI?

Patient: An old girlfriend performed oral sex on me and I ejaculated in her mouth. She appeared healthy and I did not notice any sores, blisters, or lesions on her face or in or around her mouth. There was also penetrative sex, but a condom was used. Before the sex I asked her if she was clean and she said “yes” and that she is routinely tested for sexually transmitted infections and is as careful as one can be with sex. I had a developing cold at the time. About 5 days later, my cold was going away, but I had some minor aches and pains in my groin, upper thighs, and testicles. Not severe, but there was discomfort. The feeling in my testicles was the same as that when I had a hernia years ago. Anyway, I told her of this and she mentioned to me she had been tested since our encounter “for everything” and she had “no diseases” and she mentioned to me that it had been “quite awhile” since her last sexual encounter. I have no other symptoms and my cold is almost gone, along with the pain I was experiencing. I know I was clean before our encounter, which was 8 days ago. Should I get tested for sexually transmitted diseases, and how long should I wait before getting tested to ensure accurate results?