Lump on left testicle that seems to change in size

I'm 16 now but I first noticed the lump just over 2 years ago and it is a soft-ish lump that seems to change in size. Sometimes I can hardly feel that it is even there. It doesn't cause any pain but can occasionally feel a little bit uncomfortable. It has a sort of texture to it so it's not completely smooth but I was just wondering if it's something to worry about or not. I also do not have any specific symptoms that I've had to worry about.