Okay so I have been having symptoms of a yeast infection but I feel super tender ans swollen around and on KY vagina. ... What can cause this?

Yeast Infection. The yeast infection can cause inflammation of the walls of the vagina causing some of your symptoms. Try over the counter monistat, and is no relief, consider anti fungal tablets (fluconazole). Probiotics also help improve the vaginal balance of flora and recurrence. Make sure to wear cotton underwear and avoid excessive moisture of vaginal canal as these promote yeast growth.
Yeast or Bacteria. If you do not respond to antifungal regimens, it is not uncommon to have a bacterial infection which can mimic the symprots of a yeast infection. Bacterial vaginosis is one of the most common causes of vaginal discharge.Vulvitis is another possiblity as is trichomoniasis, chlamydia and gonorrhea. Viral infections such as herpes or papilloma virus may co-exist but present with different symptoms.