Chlamydia sometimes infects the upper gastrointestinal tract, mostly by swallowing or by infection of the pharynx (throat) by oral sex. However, it causes no symptoms at all and is not likely the cause of an "irritated stomach".

If in doubt, i.e. if at risk for chlamydia (new partner recently, partner with other partners, etc), get tested routinely. But not because of this symptom; and you only need testing of the genital tract, i.e. vaginal swab or urine.

I hope this has been helpful. Let me know if anything isn't clear. Best wishes and happy holidays--

HHH, MD