Hello Thanks for query . Based on the facts that you have narrated I would state that pain at the top of the left testicle radiating up to groin and lower abdomen with a bump on the top of testicle is most likely to be due to infection of Epididymis (Epididymitis). Consult qualified Urologist for clinical examination and get following basic tests done to establish diagnosis 1) Urine routine and urine culture 2) Ultrasound Scanning of scrotum 3) Semen examination with Semen culture In the mean while start taking broad spectrum antibiotic like Cefotaxime along with anti inflammatory drug like Diclofenac twice daily . Further treatment will be decided by him based on the results of these tests and final diagnosis . Dr.Patil.