I've been having odourless yellow discharge for a month now and my gynaecologists just wants to talk. is it possible to find out with no exam?

Nope, need exam: Too little info; can't even guess at the cause of your vaginal discharge, except that colored discharge (yellow, tan, green, etc) often is due to infection. If you are age 15-30 and sexually active, STDs (gonorrhea, chlamydia, others) are possible. You can't self diagnose; see your gyn, for exam as well as "just talking". Good luck!