Lately I've been getting an itchy cl**. Its on one side, on the outside of it. What can be causing this? I have no yeast infection, nothing like that. I have a monogamous partner, (we are together 24/7 living together so there is zero possibility of an STD). It gets worse after sex or orgasm, even the morning after. Otherwise it just randomly gets itchy. There is no mark or bump or anything else. No discharge, nothing else abnormal.

Any ideas?