Lump like thing on testicles

Hi

 

so recently I saw a lump like bulge, fairly small, on the left side of the scrotum. When I investigate, by not applying pressure but rubbing, It feels like a ball, but when I put pressure it's either disappearing or it isn't a budge but a vein or something because it feels like. Maybe I'm feeling the wrong thing I don't know. I also don't know if they are related but I have an aching pain constantly around that area. At first (when I didn't notice the bulge) I thought it was just my squashing them but it happens when there are no where near my legs and hang free. I'm going to call a gp anyways because of Covid can't go for a full check up, but I thought if anyone could help before then because obviously I can't have the physical check up.