Hi, read and understood your history of left testicle growing than the right one and hurts even on touch. You have this problem for 4 days and worried about the growth or so. If I were your treating Surgeon, I would have taken the sample of the urine for the culture and sensitivity and other tests of blood and sent you for an urgent ultrasonography and color doppler of the scrotum and abdomen particularly for genito-urinary system. And started on appropriate antibiotic and anti-inflammatory medicines like Ibuprofen and supportive medicines. -My additional instructions would have been to use scrotal support -Drink plenty of oral fluids to keep urine diluted. - Take full bed rest as hanging testicles cause more pain and discomfort. Ultrasonography would give the definite diagnosis whether this is a orchitis or epididymo-orchitis. and the treatment would have been continued till you are cured. Since the antibiotics are prescription medicines you need to take the prescription from the local Doctor and a referral for investigations and Urologist.