It seems to be calculus u need scaling. Visit nearby  dentist for d same . Follow Proper brushing technique. Advice to use mouthwash  twice daily .

Looks like calculus deposition. When tartar deposits on the teeth become hard and calcify with time they are known as calculus. Gum tightness is also because the calculus has started to impinge on your gums. I would advice you to get scaling/cleaning of your teeth done. That will improve the tightness also that you can feel in your gums and even the slight pain that you are experiencing.

Periodontist{pyrea}