Testicular cancer?

alright ive been to the doctor twice now, because of pain in my left testicle...the first time he told me it was something ( i dont remember) and gave me some pills which didnt work...the second time he said it could an infection and gave me antibiotics (which didnt seem to do anything, although it has only been 1 day)...he said he didnt see any swelling, or no mes,i feel a big lump on the top of my left testicle but didnt bring it up cuz im stupid, but he also told me to go to a urologist....but he didnt say why...what could i have, BTW im 16