Thank you for your query.
Your lower abdomen, groin and pelvic areas have numerous muscles that work together to support and weight you may carry as well as support internal organs.
For a male, the pens, testes and
scrotum (outside the body) are connected by small tubes, muscles and ligaments to other organs in the abdomen (bladder,
prostate).
It is possible to have injured one of these small structure when you lifted that couch especially if you didn't carry the weight on your legs.
You can find out by putting weight on your left leg (keep it slightly bent at the knee) and lifting your right leg. If you feel the pull, then it is due to the strain. This will go away if you just the care not to strain it.
If the testicle is warm (compared to the other one) or red, tender to touch, swollen or pain intensifies, the cause could be something else altogether (stones, infection for instance). If this occurs, go to your Physician right away.
Hope this helps. Please get back to us if you need further clarification.
Wish you good health