Final answer:
Linna most likely has genital herpes, a sexually transmitted infection caused by the herpes simplex virus, characterized by painful sores in the genital area that recur throughout life.
Step-by-step explanation:
Given the symptoms described, Linna most likely has genital herpes. Genital herpes is a sexually transmitted infection (STI) caused by the herpes simplex virus. This virus is characterized by frequent outbreaks of painful blisters or sores in the genital area. These blisters typically resolve on their own; however, the virus remains in the body for life and may cause repeated outbreaks. These outbreaks can be triggered by factors such as stress or illness. Unlike genital herpes, the other STIs listed, such as chlamydia, HIV, and syphilis, commonly have different initial symptoms and progression.