I have 3 rather big red bumps on my scrotum, they have been there for one or two years, are hard, and do not hurt. what could these be?

There are various possible causes of lumps on your scrotum including testicular tumor, torsion, infections, hernia, varicocele, hydrocele, spermatocele, & hematocele. You should be examined by a urologist as soon as possible for proper diagnosis & treatment. I wish you well with your health!

It sounds like the bumps are on the scrotal skin. They may be sebaceous cysts, whicha re common and not dangerous. The best option would be to see a urologist for diagnosis and treatment