CAn a man have Clamydia and still test negative and have no symptoms at all? How likely is it for a woman to be infected for months and not no it.

The thing about chlamydia is the symptoms can be hard to notice. So a woman can be infected for a while and have no idea. And you can test negative sometimes even if you do have it. Many doctors recommend though that if you've been with someone who has chlamydia you receive treatment even if you don't test positive.