What to do if no uti, sti or thrush yet still itchy and sore?

Atrophic vaginitis?: At your age (44), a good bet is atrophic vaginitis due to low estrogen, especially if you have other evidence of menopause. Yeast infection (thrush) might still be possible; it can be difficult to diagnose with certainty. Another possibiliy is desquamative interstitial vaginitis. Keep working with your doctor, preferably a gynecologist. Good luck.