see basically oral hygiene maintenance is like the standard protocol.. mainly brush u teeth twice daily..rinse ur mouth after every meal.. make sure no food particle is stuck..as u say u feel it comes from back of it mouth there might be a chance tht ur 3rd molar tooth or wisdom tooth might be partially out and tht there might be food lodgement in that area..
Next Steps
so for time being given the covid..so at home u can jst use a mouth wash after brushing and rinsing mouth after meals and night brushing
Health Tips
so better get a scaling down after the situation of covid is like ok in ur area and get checked up for cavities and wisdom teeth as well..