Hard lump on left testicle

Hello,

I wanted some opinions on what this might be. I've had a small hard lump on the topside of my left testicle since I can remember being a teenager. I'm now a 23 year old adult and the lump has not grown and has remained there.

However, when pressure is applied, it gives off a nauseous feeling in my stomach and is quite uncomfortable.

I guess as I'm getting older I want to make sure this couldn't be anything too serious.

Any opinions on what this might be are appreciated.

Thanks!