Is a pea sized lump on my neck dangerous? it's on the left side, about 2 inches above collarbone. tender but not painful, and red.

Lymph node: There are thousands of lymph node located around the body that help screen out germs in the body serum. There are many in the neck, head ; behind the ear. At rest these are often 1/4 inch in diameter and may grow to marble sized when reacting to a stimulus. Bug bites, or viral infections can increase their size.They should shrink down to nl size over a few wks if pain not gone then have it chkd.