Hi. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns... As per your complain pain in tooth during flossing can occur due to a few reasons like in case if you floss between two teeth that have a very tight contact then pushing the floss to and fro could lead to lateral pressure on tooth and at times excessive pressure can lead to pain.. In case if there is hitting of the gums while inserting the floss between the teeth as well as while flossing there is a possibility that there is injury to the gums and initially it may not cause any symptoms but now after persistent thrust to the gums there can be pain in the gum as well as the teeth in that area.. One possibility is also there that there is infection in the side wall of tooth and when the floss touches that area there is outburst of pain and sensitivity.. In case if you do not floss regularly then also there are chances of getting pain while flossing, also vigorous flossing motion can lead to pain and discomfort as the contacts between teeth are tight.. You should consult a dentist and get evaluated for tooth decay as well as gum inflammation and if any of it is present treatment of the same can help.. Also get a proper flossing demonstration done so tat you floss effectively but do not injure your gums.. Hope this information helps.. If you find the answer helpful please give me a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..