See your doctor. See your doctor to have it evaluated. Many possible causes.
Depends where. Where/ how big/ painful or not/ adherant to surrounding tissue or not........Any weight loss/ fever etc helps pmd to localse the problem and give further advise.
It depends. It depends on the location and the size of the lymph nodes. If they are bigger than 1.5-2 cm, or if they are continuing to increase in size, then a biopsy should done to find out the cause. Lymph nodes are commonly swollen due to infections or inflammation. They may also be increased in size due to cancer of the lymph nodes, a condition called lymphoma.
Often it is from inf. Most often, infections cause lymph nodes to swell up; they are usually painful. But painless swelling of lymph nodes can be more serious and often it is caused by cancer of the lymph nodes (lymphoma) or spread of cancer from inside into lymph nodes will cause them to swell up.
Many things. Many causes for enlarged nodes, both malignant and not. You need to see a doc for a good physical exam and maybe additional tests. Do it asap. Best to you.
Get it evaluated. It means that it absolutely needs to be evaluated to determine the cause. That includes, blood tests, scans and a possible biopsy of a node. Do not delay.
Infection. This is usually a sign of infection. You should see your doctor to get worked up for the infection and treated.