after USG there is no pathology means u need not to worry.
testes is attached to cord like structure known as vas deferens so sperm can travel from testes to urethra
what u feel swelling is epydidymis and is attached to one pole of the testis
it is normal to have pain if u press it as it is very sensitive structure.
so dont be scare and be relax
still u feel that there is something then take oinion of urologist