Possible gum infection from trapped food?

It may or may not be a coincidence depending on what you had been eating when you noticed the pain start. It is quite possible you have something stuck in there if you have any pocketing spaces between your gum and your tooth. Or it is possible that it is unrelated and it's just an infection or abcessed tooth. You didn't say how old you are but if your wisdom teeth are not fully erupted that could be a source of your pain as well. There is no way to know for sure with out seeing a dentist and leaving it alone and treating it at home is not going to help anything. The mouth is a gateway to the rest of the body so if you have any infection in your mouth and you don't treat it it can easily lead to other infections and sickenesses. If you have no insurance try to find a free or low cost dental clinic in your area. You should go to the ER either way, most hospitals have a Dental Staff or residents who can treat you for this issue. If none of those are options call some dentists in the phone book and ask if they do payment plans or offer any discount rates for people who don't have insurance. Either way they have to treat you. Don't let this go, it's not going to get better on it's own. Good luck.