Chlamydia infection results in an inflammatory process- cervicitis.

Based on the anatomy  of the female genitalia, the innervation is either " somatic" or  "visceral". Where the inflammatory process affects parts that have somatic innervation, symptoms of pain and discomfort may be elicited. Where parts affected have the "vegetative" or visceral innervation, the client may present as asymptomatic. You may want to refer to the following among others.

http://www.mum.org/souinner.htm 

Hi Dr. Roseline, thanks for your reply. I am still a little puzzled, based on what I understand, some of the Chlamydia-infected patients experience intense pelvic pain due to underlying pelvic inflammatory disease (PID), this proves that there is nociceptive transmission from the reproductive tract. As for the types of innervation as mentioned, if I am not mistaken, it has to do with the nature of pain. Somatic pain is localized and easily pinpointed, while visceral pain is non-localized and diffusive. Both of which generally causes discomfort in patients. In chlamydia cases, whether it is asymptomatic or symptomatic, inflammation happens in these patients. So based on your clinical experience, do you have any idea why some patients develop PID and experience pain while some are not? Thanks for your time.

Chlamydia is sometimes asymptomatic in women and persons with female reproductive organs. The majority of chlamydial infections are asymptomatic, with no symptoms occurring

in up to 75 percent of women and 50 percent of men. Most cases remain undiagnosed as such. The focus of chlamydia prevention practices is more on women because they have more sexual health-related interaction with health care, i.e. cervix smear, oral contraceptives, pregnancy and IUD insertion.

Patrick W Dielissen (2013). Chlamydia prevalence in the general population: is there a sex difference? a systematic review. Retrieved from Article Chlamydia prevalence in the general population: Is there a s...