You are unnecessarily casting doubts about your Right testes. Whether working or not, its mere presence has given you the hormones to have sexual thought and to produce sperms. .
You may be having a varicocoele which is enlargement of veins in scrotum.
If you feel that the left testis moves at sex and right doesnt, it may be normal, as both dobt need to have equal size, shape or movement.
Next Steps
Get evaluated by a urologist ir andrologist