I have a small lump right under my jaw. it is a little sore. i also have horrible teeth and was wondering if it could be and infection in my jaw?

It could be: Any swelling is a concern. Since you said that you also have "horrible teeth" you should definitely start with a visit to your dentist to rule out a dental infection. Be aware that a dental infection can move on to other parts of your body, so you don't want to leave that and hope it just goes away!

Possible: A small lump could be a developing abscess or perhaps a slightly enlarged lymph nodes from an infected tooth. Because of the dangers associated with an abscess, especially in the lower jaw, i would get a proper evaluation from a dentist so you can be sure of the cause. This will also give you the opportunity to see what options are available for treatment.