Could you tell me if the swollen lymph node is painful does that rule out cancer?

Not absolutely: A painful, swollen lymph is most likely an inflammatory event, and should recede. However, if it persists, further investigation will be necessary. An enlarging, non-tender node(s) can be cause for concern. See your doctor.

Monitoring Centers: Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells and digested food. Lymph nodes "taste" the lymph for anything bad like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well.