Small movable lump under chin. next to jaw line near the joint/hinge. it is sore to the touch. have to push up underneath chin to feel it.light smoker?

Lymph node: It is likely an inflammed lymph node and the reason may be anywhere in its vicinity- teeth, ear, etc.

Lymph node.: That sounds like a lymph node, which could enlarge in response to an ear or sinus infection. If it eventually goes away completely, say in two to four weeks, then there's no cause for concern, especially if you have symptoms of said infections. If it does not go away, you may want to have it looked at - sometimes we need to take these out for definitive diagnosis if they linger.