What could be a problem if the vagina is red on the inside and a little itchy on the outside. no smell, no discharge.

Uncertain: Have you been using vaginal douching products? Undue friction by clothing or with sex? Symptoms of a yeast infection may include: burning, redness & itching of the vulva; burning with urination & vaginal intercourse. It could present with a clumpy, white, vaginal discharge with no odor or sometimes the discharge isn’t apparent.