This doesn't sound like epididymitis, which does not start with a "lump in the lower abdomen" that extends into the scrotum; and epididymitis involves the testicle itself. Severe pain (which presumably you would have mentioned) is the dominant symptom in sexually acquired epididymitis, and the swelling of the testicle usually is diffuse, not just a discrete lump. And most (but not all) sexually acquired epididiymitis is associated with symptomatic urethritis, i.e. abnormal penile discharge and pain or discomfort on urinating.
In any case, you will never know for sure about STDs as a cause; the azithromycin will have eradicated either gonorrhea or chlamydia, the almost-exclusive causes of sexually acquired epididymitis. Self-treatment was not a smart move. But since epididymitis is extremely unlikely, it probably makes no difference.
As to what you have, I can only speculate. A mass starting in the abdomen and extending into the scrotum sounds most like a hernia. You are right to be concerned about testicular cancer, the most common malignancy in young men. However, if you are right that the lump "did not extend to the testicle itself" then it almost certainly isn't cancer (and also not epididymitis). Other common causes of scrotal masses include hydrocele (a fluid-filled cyst), spermatocele (sperm-filled cyst in the spermatic cord, the "cord" you can feel that leads upward from each testicle), fibroma (fibrous tumor), lipoma (fatty tumor). All of these are benign, with no serious health outcome.
Bottom line: Don't worry much about an STD or other serious outcome. But see a health care provider soon for a definitive evaluation.
Good luck-- HHH, MD
P.s I had oral sex with both woman, gave not recieved. Can you get an infection this way?
No, you can't get a genital infection by oral exposure to another person's genitals.
HHH, MD
Doc,
Thanks for the info. It actually feels like the vas deferen on the right side is hard down to the epididymis, but the epididymis is not hard nor is the testicle. The swelling in the abdomin is the vas deferen entering the body. The groin does not hurt to touch but I do notice mild discomfort. Any additional info would be appreciated.