Enlarged submandibular lymph nodes for about 6 weeks. us showed multiple straight prominent lymph nodes measuring 0.9 x 1.1 x 1.8 cm and 1.5 x 1.0 x 1.6 cm. cbc normal besides wbc (3.0 l). could this be from 2nd covid shot which i had 2 months ago?

Lymph nodes are your body’s way of eliminating infection, in this case, head and neck. They can persist days to weeks and should shrink with time. If they are small, usually no problem. At six weeks it is reasonable to see your doctor to discuss and to have a good physical exam. Most likely this will resolve. It's probably not your vaccine - that would be armpit nodes.

Covid shot is an unlikely explanation. You may feel the nodes every couple of weeks, if any of the lymph glands doubles in size, becomes painful, ulcerates, or other nodes become enlarged, or you develop fever, or lose weight, you should see a doctor. Wish you good health!