Painful testicular lump?

Im 16 years old andI went to the doctors 2 months ago because i had a painful lump on the very top of my left testicle, the bump itself doesnt really hurt to touch but it hurts around it...i have a similar bump on the top my right testicle but its a little smaller and not painful ... i dont remember what he said was causing the pain (because im an idiot) but he gave me some IBU 800mg to take...ive been taking it and pain went away for a lil while but its recently come back...should i just not worry about it? and what could it be?