Found red bumps&white coating on very back of tongue. spicy food?seasonal allergies?oral std? i've had spicy food,weather has changed,maybe std? :(

Tongue papillae?: Everyone has a row of 7-12 large (2-3 mm) papillae across the back of the tongue, called circumvallate papillae, perhaps what you have noticed. Google it for photos to compare. Entirely normal, not caused by any of the things you mention. No STD is a likely cause of any kind of painless bumps in the moth. But since STDs are on your mind, you're probably at risk, so get tested. Good luck!