In men, chlamydia is the commonest cause of urethral discharge from the penis. Sometimes chlamydia can cause mild irritation at the end of the penis, which disappears after two or three days. Many men suffering some discomfort will wait to see if it goes away. Unfortunately the discomfort may disappear but the infection can still be present. They can therefore transmit it to a sexual partner and also risk the complication of swollen testicles.
Chlamydial infection can affect sperm function and fertility in men.
If in doubt go and have a test taken . Condoms are effective in preventing spread of the infection. Obviously there is no point in one half of a sexual partnership getting treated for sexually-transmitted infection unless the other half also gets treated. Otherwise the untreated partner just gets re-infected. Getting repeated infection can cause far worse consequences from the point of view of fertility in women.