My left jaw muslce is hurting when i eat?!

its right where the jaw line starts curving up under the ear...it feels like it might be a lymph node but im not sick or anything and didnt understand where the pain came from or how i could get rid of it. when im not chewing or when i talk, its fine. but as soon as i chew something or clench my teeth i feel it there. it actually only came up about a day or 2 ago...any help??