Got red scrotum and anus itchy and very painful?

Scrotum, testis pain: Scrotum or testicle pain means a trip to the doctor because a testicle's blood supply can be twisted off (torsion). When that happens, the testicle can die. Other causes of testicle pain include trauma, infection, twisting of an appendix of a testicle (a small lump near a testicle), etc. Since one usually cannot tell for sure if his testicle is twisted, he needs an exam by a clinic or ER doctor.

How bad ?: If your really in pain that interferes with any activity go to the ER now. If it just itches & is uncomfortable you may just have jock itch, the lay term for a fungus infection in your groin & genitals. That can be managed at home with a variety of anti fungal creams/lotions/sprays. Your post is a bit vague to know what you mean by painful.