Stiff neck, without fever, headache, etc, simply is not a symptom of any infection and
certainly not of meningitis
. (Nobody gets meningitis
due to any cause without fever, bad headache, headache, and feeling horribly ill.) Neck pain, back pain, etc generally is caused by muscle spasm and undoubtedly happens to tens of thousands of people each day in the US, and a several thousand each day catch chlamydia, and a hundred times that number have new sex during any one week.