Hi,
Thank you for posting your query. I had gone through your problem. Normally there should not be any gaps between teeth. But because of gum diseases in some individuals gaps will be formed between the teeth. Some times infection is seen beneath the gums. when ever food is accumulated in these areas wage to moderate pain is felt. Pain will be severe if chicken like substances are accumulated in these areas because of putrefaction by the micro organisms. It is not possible to remove that infection by using floss or by using mouth wash. profession treatment is necessary to get rid of the problem. So i would like to suggest you to meet the gum specialist i.e., periodontist. Hope my explanation would satisfy your query.

Thanks for using Health Care Magic.

Read your query.

Taking into consideration of your signs and symptoms , food lodgement can be due to decay in any of the molars which is causing you the pain.
It can also be because of a deep pocket in the gums which is a becoming a little difficult for you to clean and due to food lodgement it is causing the sensitivity.

I would suggest you to visit your local dentist and get it checked up .
If there is decay, it can be filled and if there is presence if a deep pocket please continue with the cleaning of your teeth so that it will reduce giving you relief from the discomfort.

Do chlorhexidine mouth wash gargling.

Thanks and regards .

Any further queries are always welcome.