Soft bump on left testicle?

Hi! I'm 19 and a guy. I feel really worried - sick with nerves, as i found a bit of a bump on my left ball. If i lightly press my "sack" i cant feel it, but if i pinch the end/bottom of my ball, i can. It's soft, doesn't hurt or anything, and it kinda moves around. It feels like its like one or two little fatty soft bubbles or something. If i do this in the shower in warm water, it's feelable, if my balls are cold, it's not as much. My other ball feels a bit fatty too at the bottom so i dont know if this is just normal, but it's hard to work out if the ball on the left has this bigger fatty bit so im not sure if its normal or not. I feel sick because i'm worried it's cancer. I was up at almost half 1 in the morning, just feeling around it constantly. If i stand up it is more feelable, but if im lying down, its a bit harder to find and doesn't feel as bumpy. What could it be? I think i've had it a while, or always had it, but i've just been thinking more of it for the past 2 days. I'm thinking about going to the doctors... Im scared though, and i'm shy... I havent told my mum (my dad and her split up so i cant ask him, and wont over the phone), and my penis is a bit on the small side and i find things like this embarassing. Thanks!