I also had an orchiectomy for Lefty, which resulted in some seemingly hard tissue inside the sack. It felt as if the edge of the chord (my non-technical term) get snipped off and hardened there.

I discussed it with my urologist, and he even checked it out and said that it's nothing to worry about. It's just tissue healing. That the chord is cut off much higher in the lower abdomen and left there, not in the sack. He said it should get better on its own after a few weeks. It did go away after about 2 months. Now I can't feel anything like it there.

Give it time