Hello, I have noticed a lump under my chin, centered between my lower jawbones. this lump is very painful and if I look up it feels like stretching a pulled muscle. I am very worried about it. Can anyone tell me what this could be and what I should do? I have had it for 2 days now, and it seems to be getting more painful. I had a cold sore earlier. What could be causing it? Please help!!! I am 29 years old male.