Hi ! Please let me know if your job requires prolonged standing which may lead to the inflammation of either the testis or epididymis
or both. This may cause swelling and pain in the testicles. The testis draws its innervation from the abdominal nerves, and so the pain in testes can radiate to the abdomen which can be excruciating and unbearable at times. I suggest you to wear a good scrota support, along with some anti inflammatory drugs with an option for a course of antibiotics if need be and advised by your doctor. You should also get your routine blood and urine tests done. If the problem persists, then you may have to see a urologist/surgeon for clinical evaluation who may advise you to undergo an ultrasound
of both testes. Good luck.