I have a sudden onset of a swollen and painful lymph node under my jaw accompanied by painful swallowing. see a doctor or watch and wait?

Adenitis: I would see a doctor if it's affecting your swallowing, the node is red and tender, or you have a fever. Bacterial lymphadenitis requires antibiotics. Most times, viral infections cause inflamed, tender nodes, though the addition of the above symptoms makes ruling out lymphadenitis important. Please at least discuss with your doctor in more detail.